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Abstract: Published data on the Fourier transform spectrum of 12C2HD in the overtone range, from Liévin et al. [Chem. Phys. 10 (1995) 419] and Abbouti Temsamani and Herman [Mol. Phys. 79 (1993) 359], are revisited by taking into account the (1/255) anharmonic resonance. A dedicated Hamiltonian is used to build interacting clusters. New vibrational parameters are obtained which account for previously reported anomalous spectral features.
BibTeX:
@article{AbboutiTemsamaniHerman1996,
  author = {Abbouti Temsamani, M. and Herman, M.},
  title = {Anharmonic resonances in monodeuteroacetylene (12C2HD)},
  journal = {Chemical Physics Letters},
  year = {1996},
  volume = {260},
  pages = {253-256}
}
Abstract: The spectrum of scandium was recorded in the infrared region using a high resolution Fourier transform spectrometer and a hollow-cathode discharge. Hyperfine structures of the lines connecting the 3d24s and 3d4s4p level systems of Sc45I were observed between 4000 and 5000cm-1. The structures were not completely resolved but the individual line contributions to the complex profiles were simulated using the 3d24s 4FJ hyperfine structure constants previously measured with a high precision by laser techniques. We investigate the possibility of extracting the hyperfine constants of the 3d4s4p levels from a least-squares fit of the line profiles, assuming a Doppler lineshape and theoretical relative intensities. New results are presented for 12 levels.
BibTeX:
@article{AboussaidCarleerHurtmansEtAl1996,
  author = {Aboussaïd, A. and Carleer, M. and Hurtmans, D. and Biémont, E. and Godefroid, M.R.},
  title = {Hyperfine structure of Sc I by infrared fourier transform spectroscopy},
  journal = {Physica Scripta},
  year = {1996},
  volume = {53},
  pages = {28-32},
  doi = {10.1088/0031-8949/53/1/004}
}
Abstract: We are investigating the hyperfine quenching of 1s2p 3P0o for the three heliumlike ions F7+19, Na9+23, and Al11+27 in the multiconfigurational Hartree-Fock-Breit-Pauli scheme. The configuration expansions are generated with the active-space method and are increased in a systematic way, allowing the convergence of the calculated parameters to be studied. A careful comparison is done with the pioneering work of Mohr using a perturbation approach [Beam-Foil Spectroscopy, Atomic Structure and Lifetimes, edited by I. Sellin and D. Pegg (Plenum, New York, 1976), Vol. 1, pp. 97-103]. In the present calculations the orbital and spin-dipole magnetic contributions, which were previously neglected, are added to the dominant Fermi contact interaction term and a detailed analysis of the hyperfine induced transition rate is done in order to learn how to get an accurate description of the property in the multiconfiguration Hartree-Fock-Breit-Pauli approximation. © 1995 The American Physical Society.
BibTeX:
@article{AboussaidGodefroidJoenssonEtAl1995,
  author = {Aboussaïd, A. and Godefroid, M.R. and Jönsson, P. and Froese Fischer, C.},
  title = {Multiconfigurational Hartree-Fock calculations of hyperfine-induced transitions in heliumlike ions},
  journal = {Physical Review A},
  year = {1995},
  volume = {51},
  pages = {2031-2039},
  doi = {10.1103/PhysRevA.51.2031}
}
Abstract: Mass spectrometric technique has been employed to analyze the molecular beams effusing from mullite Knudsen cells containing Sn and alloys of Cu, Ag, and Au with Sn. From the experimental intensities of monatomic and diatomic species and the vapor pressure of Sn, the following dissociation energies are obtained: D0° (Sn2) = 45.8±4 kcal/mole, D 0° (AgSn) = 31.6±5 kcal/mole, D0° (AuSn) = 57.5±4 kcal/mole, D0° (CuSn) = 41.4±4 kcal/mole.
BibTeX:
@article{AckermanDrowartStaffordEtAl1962,
  author = {Ackerman, M. and Drowart, J. and Stafford, F.E. and Verhaegen, G.},
  title = {Mass spectrometric study of the gaseous molecules above AgSn, AuSn, and CuSn alloys},
  journal = {The Journal of Chemical Physics},
  year = {1962},
  volume = {36},
  pages = {1557-1560},
  doi = {10.1063/1.1732778}
}
Abstract: The molecules AuCr and AuPd have been identified. From data for the reaction Au2+X=AuX+Au, and D0°(Au2) = 51.5 kcal/mole: D0°(AuCr) = 50.4±3.5 kcal/mole, D 0°(AuPd) = 33.3±5 kcal/mole.
BibTeX:
@article{AckermanStaffordVerhaegen1962,
  author = {Ackerman, M. and Stafford, F.E. and Verhaegen, G.},
  title = {Studies of the vapors of the system Au-Cr and Au-Pd by mass spectrometry},
  journal = {The Journal of Chemical Physics},
  year = {1962},
  volume = {36},
  pages = {1560-1562},
  doi = {10.1063/1.1732779}
}
Abstract: SCF-CI calculations were done on tetratomic oxygen complexes at various geometries. The results point to the existence of a metastable covalent molecule O4 completely different from the van der Waals structure (O2)2 detected experimentally. At its equilibrium geometry, the O4 molecule is a quasi-square (r(OO) ≈ 1.4 Å), slightly twisted out of plane, corresponding to the symmetry group D2d. The activation energy of the reaction O4(1Ag) → 202(X 3Σ- g) is found to be ≈ 15 kcal/mole, that of the inverse reaction, ≈ 75 kcal/mole. © 1980.
BibTeX:
@article{AdamantidesNeisiusVerhaegen1980,
  author = {Adamantides, V. and Neisius, D. and Verhaegen, G.},
  title = {Ab initio study of the O4 molecule},
  journal = {Chemical Physics},
  year = {1980},
  volume = {48},
  pages = {215-220},
  doi = {10.1016/0301-0104(80)80051-6}
}
Abstract: We report the first operating heterojunction bipolar transistor with a base made of a GaAs/Ga1-xAlxAs superlattice (superlattice bipolar transistor or SBT device). The MBE growth conditions of such structures are described and the importance of a careful X-ray characterization of the superlattice parameters is pointed out. A drastic variation of the SBT current gain with only one superlattice parameter, the barrier width, is related to the competition between hopping and Bloch conduction perpendicular to interfaces. Future optoelectronic device possibilities are also commented upon. © 1987.
BibTeX:
@article{AlexandreHarmandLievinEtAl1987,
  author = {Alexandre, F. and Harmand, J.C. and Lievin, J.L. and Dubon-Chevallier, C. and Ankri, D. and Minot, C. and Palmier, J.F.},
  title = {A new GaAs/Ga1-xAlxAs superlattice transistor grown by molecular beam epitaxy},
  journal = {Journal of Crystal Growth},
  year = {1987},
  volume = {81},
  pages = {391-395},
  doi = {10.1016/0022-0248(87)90422-2}
}
Abstract: We report an investigation of two effects related to the low quality of MBE Ga1-xAlxAs layers and of the Ga1-xAlxAs/GaAxAs heteroiinterface (resulting from the growth of Ga1-xAlxAs on top of GaAs), as compared to the GaAs/Ga1-xAlxAs one. First, a surface roughness is observed for Ga1-xAlxAs layers grown under specific conditions, and notnot for the AlAs and GaAs binary compounds. Second, the analysis of the extrinsic 4 K photoluminescence of the GaAs single quantum well suggests that impurities are trapped in the GaAs layer close to the Ga1-x-GaxAs/GaAs heterointerface. This effect is strongly reduced by growing before this interface thin prelayers, acting as impurity trapping centers. This improvement is found to be more efficient for GaAs than Ga-xAlxAs prelayers. The relation between these two mechanisms is discussed. © 1986.
BibTeX:
@article{AlexandreLievinMeynadierEtAl1986,
  author = {Alexandre, F. and Lievin, J.L. and Meynadier, M.H. and Delalande, C.},
  title = {GaAs/Ga1-xAlxAs and Ga1-xAlxAs/GaAs heterointerfaces grown by molecular beam epitaxy},
  journal = {Surface Science},
  year = {1986},
  volume = {168},
  pages = {454-461},
  doi = {10.1016/0039-6028(86)90875-7}
}
Abstract: This corrigendum provides a new version of one of the 3 supplementary data files associated with the article A. Alkadrou et al., J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171, namely the HITRAN-formatted linelist generated as described in section 5 of the article. Indeed, the Ka and Kc labels of the upper levels of a number of transitions belonging to the ν10, ν7 and ν4 bands listed in this supplementary data file were found to be incorrect. The linelist provided with this corrigendum corrects these erroneous assignments, and provides Ka and Kc labels for all the upper levels. © 2017 Elsevier Ltd
BibTeX:
@article{AlkadrouBourgeoisRotgerEtAl2017,
  author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.},
  title = {Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2 h top data system” (Journal of Quantitative Spectroscopy and Radiative Transfer (2017) 190 (88) (S0022407315303162) (10.1016/j.jqsrt.2016.05.024))},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {190},
  pages = {88},
  doi = {10.1016/j.jqsrt.2017.01.007}
}
Abstract: A global frequency and intensity analysis of the infrared tetrad of 12C2H4 located in the 600-1500cm-1 region was carried out using the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. It relied on spectroscopic information available in the literature and retrieved from high-resolution Fourier transform infrared spectra recorded in Brussels in the frame of either the present or previous work. In particular, 645 and 131 line intensities have been respectively measured for the weak ν10 and ν4 bands. Including the Coriolis interactions affecting the upper vibrational levels 101, 71, 41 and 121, a total of 10 757 line positions and 1645 line intensities have been assigned and fitted with global root mean square deviations of 2.6×10-4cm-1 and 2.5%, respectively. Relying on the results of the present work and available in the literature, a list of parameters for 65 776 lines in the ν10, ν7, ν4 and ν12 bands of 12C2H4 was generated. To the best of our knowledge, this is the first time that a global intensity analysis is carried out in this range of the ethylene spectrum. © 2016 Elsevier Ltd.
BibTeX:
@article{AlkadrouBourgeoisRotgerEtAl2016,
  author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.},
  title = {Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h Top Data System},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {182},
  pages = {158-171},
  doi = {10.1016/j.jqsrt.2016.05.024}
}
Abstract: The internal partition function (Q int) of ethyne (acetylene), 12C 2H 2, is calculated by explicit summation of the contribution of all individual vibration-rotation energy levels up to 15 000 cm -1. The corresponding energies are predicted from a global model and constants reproducing within 3σ all 18 415 published vibration-rotation lines in the literature involving vibrational states up to 8900 cm -1, as produced by Amyay J. Mol. Spectrosc. 267, 80 (2011). Values of Q int, with distinct calculations for para and ortho species are provided from 1 to 2000 K, in step of 1 K. The total internal partition function at 298.15 K is 104.224387(47) or 416.89755(19), with the nuclear degeneracy spin factors taken as 1/4: 3/4 (astronomer convention) or 1:3 (atmospheric convention), respectively, for para:ortho species. The Helmholtz function, Gibbs enthalpy function, entropy, and specific heat at constant pressure are also calculated over the same temperature range. Accuracies as well as the missing contribution of the vinylidene isomer of acetylene in the calculations are discussed. © 2011 American Institute of Physics.
BibTeX:
@article{AmyayFaytHerman2011,
  author = {Amyay, B. and Fayt, A. and Herman, M.},
  title = {Accurate partition function for acetylene, 12C 2H 2, and related thermodynamical quantities},
  journal = {Journal of Chemical Physics},
  year = {2011},
  volume = {135},
  article number = {234305},
  doi = {10.1063/1.3664626}
}
Abstract: A complete set of calculated vibration-rotation energies of 12C2H2 (X1Σg +) is provided for all vibrational states up to 13 000 cm-1 and some at higher energies, with rotational (J) and vibrational angular momentum (l) quantum numbers such that 0 ≤ J ≤ 100 and 0 ≤ |l| ≤ 20, respectively. The calculation is performed using a global effective Hamiltonian and related spectroscopic constants from the literature [B. Amyay et al., J. Mol. Spectrosc. 267, 80 (2011)], based on the polyad model. The numerical values of all related polyad matrix elements are also provided. The model and equations for the Hamiltonian matrix elements are gathered. The experimental acetylene database used for determining the parameters is listed. � 2016 AIP Publishing LLC for the National Institute of Standards and Technology.
BibTeX:
@article{AmyayFaytHermanEtAl2016,
  author = {Amyay, B. and Fayt, A. and Herman, M. and Vander Auwera, J.},
  title = {Vibration-rotation spectroscopic database on acetylene, X1Σg + (12C2H2)},
  journal = {Journal of Physical and Chemical Reference Data},
  year = {2016},
  volume = {45},
  article number = {023103},
  doi = {10.1063/1.4947297}
}
Abstract: The ν3 C-H stretching region of methane was reinvestigated in this work using high temperature (620-1715 K) emission spectra recorded in Rennes at Doppler limited resolution. This work follows our recent global analysis of the Dyad system Δn = ±1 (1000-1500 cm-1), with n being the polyad number [B. Amyay et al., J. Chem. Phys. 144, 24312 (2016)]. Thanks to the high temperature, new assignments of vibration-rotation methane line positions have been achieved successfully in the Pentad system and some associated hot bands (Δn = ±2) observed in the spectral region 2600-3300 cm-1. In particular, rotational assignments in the cold band [Pentad-ground state (GS)] and in the first related hot band (Octad-Dyad) were extended up to J = 30 and 27, respectively. In addition, 1525 new transitions belonging to the Tetradecad-Pentad hot band system were assigned for the first time, up to J = 20. The effective global model used to deal with the new assignments was developed to the 6th order for the first three polyads (Monad, Dyad, and Pentad), and to the 5th order for both the Octad and the Tetradecad. 1306 effective parameters were fitted with a dimensionless standard deviation σ = 2.64. The root mean square deviations dRMS obtained are 4.18 × 10-3 cm-1 for the Pentad-GS cold band, 2.48 × 10-3 cm-1 for the Octad-Dyad, and 1.43 × 10-3 cm-1 for the Tetradecad-Pentad hot bands. © 2018 Author(s).
BibTeX:
@article{AmyayGardezGeorgesEtAl2018,
  author = {Amyay, B. and Gardez, A. and Georges, R. and Biennier, L. and Vander Auwera, J. and Richard, C. and Boudon, V.},
  title = {New investigation of the ν 3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra},
  journal = {Journal of Chemical Physics},
  year = {2018},
  volume = {148},
  article number = {134306},
  doi = {10.1063/1.5023331}
}
Abstract: The analysis of CW-cavity ring down absorption spectra of 12C2H2 previously reported by Robert et al. (Mol. Phys. 106 (2008) 2581) was improved in the range 6667-7015 cm -1. Some 1825 lines were newly assigned. They either belong to 105 new sub-bands, involving 69 previously unreported sub-states, or extend assignments in 35 already known sub-bands. A global fit procedure of line positions from the full 12C2H2 database containing 18 415 lines, including those newly assigned, was performed, accessing vibrational states up to 8900 cm-1. Coriolis interactions were systematically introduced in the global Hamiltonian, which also accounted for higher order vibrational constants and considered the role of higher excited bending states than before. The dimensionless standard deviation of the fit was 1.07 and 396 effective vibration-rotation parameters were determined. Two local, interpolyad couplings were evidenced for the first time. A set of 121 new lines from 12CH13CH present in natural abundance in the gas sample were also assigned. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{AmyayHermanFaytEtAl2011,
  author = {Amyay, B. and Herman, M. and Fayt, A. and Campargue, A. and Kassi, S.},
  title = {Acetylene, 12C2H2: Refined analysis of CRDS spectra around 1.52 μm},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {267},
  pages = {80-91},
  doi = {10.1016/j.jms.2011.02.015}
}
Abstract: FIR spectra of C2H2 have been recorded at 0.00096 cm-1 spectral resolution using the Canadian Light Source synchrotron facility. The analysis allowed us to assign 731 new vibration-rotation lines from 48 bands in 12C2H2, 38 of which are reported for the first time. Two additional bands are assigned to 13CH12CH. The measured line positions and calculated spectra can be made available to help in the remote sensing of acetylene in the terahertz spectral range. © 2010 Elsevier B.V. All rights reserved.
BibTeX:
@article{AmyayHermanFaytEtAl2010,
  author = {Amyay, B. and Herman, M. and Fayt, A. and Fusina, L. and Predoi-Cross, A.},
  title = {High resolution FTIR investigation of 12C2H2 in the FIR spectral range using synchrotron radiation},
  journal = {Chemical Physics Letters},
  year = {2010},
  volume = {491},
  pages = {17-19},
  doi = {10.1016/j.cplett.2010.03.053}
}
Abstract: We report new assignments of vibration-rotation line positions of methane (12CH4) in the so-called dyad (ν2/ν4) region (1100-1500 cm-1), and the resulting update of the vibration-rotation effective model of methane, previously reported by Nikitin et al. [Phys. Chem. Chem. Phys. 15, 10071 (2013)], up to and including the tetradecad. High resolution (0.01 cm-1) emission spectra of methane have been recorded up to about 1400 K using the high-enthalpy source developed at Institut de Physique de Rennes associated with the Fourier transform spectrometer of the SOLEIL synchrotron facility (AILES beamline). Analysis of these spectra allowed extending rotational assignments in the well-known cold band (dyad-ground state (GS)) and related hot bands in the pentad-dyad system (3000 cm-1) up to Jmax = 30 and 29, respectively. In addition, 8512 new transitions belonging to the octad-pentad (up to J = 28) and tetradecad-octad (up to J = 21) hot band systems were successfully identified. As a result, the MeCaSDa database of methane was significantly improved. The line positions assigned in this work, together with the information available in the literature, were fitted using 1096 effective parameters with a dimensionless standard deviation σ = 2.09. The root mean square deviations dRMS are 3.60 × 10-3 cm-1 for dyad-GS cold band, 4.47 ×10-3 cm-1 for the pentad-dyad, 5.43 × 10-3 cm-1 for the octad-pentad, and 4.70 × 10-3 cm-1 for the tetradecad-octad hot bands. The resulting new line list will contribute to improve opacity and radiative transfer models for hot atmospheres, such as those of hot-Jupiter type exoplanets. © 2016 AIP Publishing LLC.
BibTeX:
@article{AmyayLouviotPiraliEtAl2016,
  author = {Amyay, B. and Louviot, M. and Pirali, O. and Georges, R. and Vander Auwera, J. and Boudon, V.},
  title = {Global analysis of the high temperature infrared emission spectrum of 12CH4 in the dyad (ν 2/ ν 4) region},
  journal = {Journal of Chemical Physics},
  year = {2016},
  volume = {144},
  article number = {024312},
  doi = {10.1063/1.4939521}
}
Abstract: A high temperature source has been developed and coupled to a high resolution Fourier transform spectrometer to record emission spectra of acetylene around 3 μm up to 1455 K under Doppler limited resolution (0.015 cm-1). The ν3-ground state (GS) and ν2+ν4+ν5(∑u + and Δu)-GS bands and 76 related hot bands, counting e and f parities separately, are assigned using semiautomatic methods based on a global model to reproduce all related vibration-rotation states. Significantly higher J -values than previously reported are observed for 40 known substates while 37 new e or f vibrational substates, up to about 6000 cm-1, are identified and characterized by vibration-rotation parameters. The 3 811 new or improved data resulting from the analysis are merged into the database presented by Robert [Mol. Phys. 106, 2581 (2008)], now including 15 562 lines accessing vibrational states up to 8600 cm-1. A global model, updated as compared to the one in the previous paper, allows all lines in the database to be simultaneously fitted, successfully. The updates are discussed taking into account, in particular, the systematic inclusion of Coriolis interaction. © 2009 American Institute of Physics.
BibTeX:
@article{AmyayRobertHermanEtAl2009,
  author = {Amyay, B. and Robert, S. and Herman, M. and Fayt, A. and Raghavendra, B. and Moudens, A. and Thívin, J. and Rowe, B. and Georges, R.},
  title = {Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm},
  journal = {Journal of Chemical Physics},
  year = {2009},
  volume = {131},
  article number = {114301},
  doi = {10.1063/1.3200928}
}
Abstract: The body-fixed Hamiltonian developed here is expressed in terms of the atom's distance from and orientation with respect to the plane defined by the triatomic. © 1996 John Wiley & Sons, Inc.
BibTeX:
@article{AndersonSutcliffe1996,
  author = {Anderson, N. and Sutcliffe, B.T.},
  title = {The nuclear motion Hamiltonian for a tetratomic molecule considered as a combination of an atom and a triatom},
  journal = {International Journal of Quantum Chemistry},
  year = {1996},
  volume = {60},
  pages = {37-46},
  doi = {10.1002/(SICI)1097-461X(1996)60:1<37::AID-QUA4>3.0.CO;2-6}
}
Abstract: One of the most important atmospheric composition products derived from the first EUMETSAT Meteorological Operational satellite (MetOp-A) is the total ozone column (TOC). For this purpose, MetOp-A has two instruments on board: the Global Ozone Monitoring Experiment 2 (GOME-2) that retrieves the TOC data from the backscattered solar ultraviolet-visible (UV-Vis) radiance, and the Infrared Atmospheric Sounding Interferometer (IASI) that uses the thermal infrared radiance to derive TOC data. This paper focuses on the simultaneous validation of the TOC data provided by these two MetOp-A instruments using the measurements recorded by five well-calibrated Brewer UV spectrophotometers located at the Iberian Peninsula during the complete 2009. The results show an excellent correlation between the ground-based data and the GOME-2 and IASI satellite observations (R2 higher than 0.91). Differences between the ground-based and satellite TOC data show that the IASI instrument significantly overestimates the Brewer measurements (about 4.4% when all five ground-based stations are jointly used). In contrast, the GOME-2 instrument shows a slight underestimation (~1.6%). In addition, the absolute relative differences between the Brewer and GOME-2 data are quite smaller (about a factor higher than 2) than the Brewer-IASI absolute differences. The satellite viewing geometry (solar zenith angle and the view zenith angle) has no significant influence on the Brewer-satellite relative differences. Moreover, the analysis of these relative differences with respect to the ground-based TOC data indicates that GOME-2 instrument presents a slight underestimation for high TOC values. Finally, the IASI-GOME-2 correlation is high (R2~0.92), but with a mean relative difference of about ±6% which could be associated with the bias between UV-Vis and infrared spectroscopy used in the retrieval processes. © 2011 Elsevier Inc.
BibTeX:
@article{AntonLoyolaClerbauxEtAl2011,
  author = {Antón, M. and Loyola, D. and Clerbaux, C. and López, M. and Vilaplana, J.M. and Bañón, M. and Hadji-Lazaro, J. and Valks, P. and Hao, N. and Zimmer, W. and Coheur, P.F. and Hurtmans, D. and Alados-Arboledas, L.},
  title = {Validation of the MetOp-A total ozone data from GOME-2 and IASI using reference ground-based measurements at the Iberian Peninsula},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  pages = {1380-1386},
  doi = {10.1016/j.rse.2011.01.018}
}
Abstract: Multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 2p5Po2, 2p4(3P)3s4P, 2p4(3P)3s2P, and 2p4(3P)3p4So states of F19 i to determine their hyperfine constants. Several computing strategies are considered to investigate electron correlation and relativistic effects. High-order correlation contributions are included in MCHF calculations based on single and double multireference expansions. The largest components of the single reference MCHF wave functions are selected to define the multireference (MR) sets. In this scheme, relativistic corrections are evaluated in the Breit-Pauli approximation. A similar strategy is used for the calculation of MCDHF relativistic wave functions and hyperfine parameters. While correlation and relativistic corrections are found to be rather small for the ground state, we highlight large relativistic effects on the hyperfine constant A3/2 of 2p4(3P)3p4So and, to a lesser extent, on A1/2 of 2p4(3P)3s4P. As expected for such a light system, electron correlation effects dominate over relativity in the calculation of the hyperfine interaction of all other levels considered. We also revisit the hyperfine constants of 2p3(4S)3sSo5 and 2p3(4S)3p5P in O17 using similar strategies. The results are found to be in excellent agreement with experiment. © 2018 American Physical Society.
BibTeX:
@article{AourirNemouchiGodefroidEtAl2018,
  author = {Aourir, N. and Nemouchi, M. and Godefroid, M. and Jönsson, P.},
  title = {Theoretical hyperfine structures of F 19 i and O 17 i},
  journal = {Physical Review A},
  year = {2018},
  volume = {97},
  article number = {032506},
  doi = {10.1103/PhysRevA.97.032506}
}
Abstract: Theoretical and experimental isotope shifts for Ca l and Sr i levels are presented. The isotope shifts of the levels 4s6s1S0 4p2 ‘So and 4p2 1D2 of calcium have been measured between the isotopes 40, 42, 43, 44 and 48 in two-photon transitions from the Ca ground state using two lasers with different wavelengths. Results of ab inilio mass and field shift calculations are presented for these levels as well as for a number of other strongly perturbed low-lying levels in calcium and strontium using the multiconfigutation Hartree-Fock method. The ‘gradient’ and the alternative ‘Slater’ forms of the specific mass shift operator have been tested; the latter is found to be unreliable with our mchf expansions which are limited to valence correlation effects. The agreement between theory and experiment is systematically better in strontium than in calcium for the specific mass shifts. The ab inilio field shift values agree well with the trend of the observations for both atoms, although they are systematically too small. A semiempirical calibration procedure leads to very good agreement for both atoms. Core-relaxation effects are shown to be large particularly for the mass shift. © 1991 IOP Publishing Ltd.
BibTeX:
@article{AspecttBaucheiGodefroidEtAl1991,
  author = {Aspectt, A. and Bauchei, J. and Godefroid, M. and Grangier, P. and Hansen, J.E. and Vaeck, N.},
  title = {Experimental and mchf isotope shifts of strongly perturbed levels in ca i and sr i},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1991},
  volume = {24},
  pages = {4077-4099},
  doi = {10.1088/0953-4075/24/18/019}
}
Abstract: Five ortho and para bands of the ν2 umbrella mode of the NH3–Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Πs(j = 1,k = 0) ← Σa(j,k = 0) and Σs(j = 1,k = 0) ← Σa(j,k = 0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Πs/a,lower(j = 1,k = 1) ← Σa(j = 1,k = 1) and Πs/a,upper(j = 1,k = 1) ← Σs(j = 1,k = 1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν2 state (32.003(1) and 36.008(1) cm−1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν2 = 0 and ν2 = 1 states. © 2018 Informa UK Limited, trading as Taylor & Francis Group
BibTeX:
@article{AsselinBelkhodjaJabriEtAl2018,
  author = {Asselin, P. and Belkhodja, Y. and Jabri, A. and Potapov, A. and Loreau, J. and van der Avoird, A.},
  title = {Rovibrational laser jet-cooled spectroscopy of the NH3–Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*},
  journal = {Molecular Physics},
  year = {2018},
  pages = {1-14},
  doi = {10.1080/00268976.2018.1471533}
}
Abstract: Suspended particles play an important role in coastal waters by controlling to a large extent the variability of the water inherent optical properties (IOPs). In this study, focused on the complex waters of the Southern North Sea, the relationships between the concentration, composition and size of suspended particles and their optical properties (light absorption, and attenuation in the visible and near-infrared spectral regions) are investigated. Over a one-year period, field measurements were carried out along regular transects from the Belgian to the English coasts to cover a wide gradient of water masses. Results show that the area can be divided into three geographical zones, each one having specific biogeochemical and optical properties: Scheldt coastal zone (SCZ), Middle of the Southern North Sea (MSNS) and Thames coastal zone (TCZ). Concentrations of organic (inorganic) particles were always higher in the SCZ (TCZ). The MSNS was characterized by a high proportion of organic particles in low concentration. The spectral shape of particle attenuation reveals a wide range from negative to positive slopes. Particle size distributions reveal a power-law shape along the coasts (especially in the TCZ) and a bimodal distribution in the MSNS notably during the spring phytoplankton bloom. This bimodal size distribution and more precisely a size peak around 7 μm results in an unexpected negative spectral slope of the particle attenuation coefficient. Variations in the particulate mass-specific IOPs between the three regions were observed to predominate over seasonal variations. The implications in terms of inversion of IOPs into biogeochemical parameters, such as chlorophyll a and total suspended matter, in coastal waters are discussed. © 2012 Elsevier Ltd.
BibTeX:
@article{AstorecaDoxaranRuddickEtAl2012,
  author = {Astoreca, R. and Doxaran, D. and Ruddick, K. and Rousseau, V. and Lancelot, C.},
  title = {Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea},
  journal = {Continental Shelf Research},
  year = {2012},
  volume = {35},
  pages = {117-128},
  doi = {10.1016/j.csr.2012.01.007}
}
Abstract: The variability and origin of the Coloured Dissolved Organic Matter (CDOM) were studied in the Belgian coastal and adjacent areas including offshore waters and the Scheldt estuary, through the parameters: absorption at 375 nm, aCDOM(375), and the slope of the absorption curve, S. aCDOM(375) varied between 0.20 and 1.31 m-1 and between 0.97 and 4.30 m-1 in the marine area and Scheldt estuary, respectively. S fluctuated between 0.0101 and 0.0203 nm-1 in the marine area and between 0.0167 and 0.0191 nm-1 in the Scheldt estuary. The comparative analysis of aCDOM(375) and S variations evidenced different origins of CDOM in the BCZ. The Scheldt estuarine waters showed decreasing aCDOM(375) values with increasing salinity but constant S value of ∼0.018 nm-1 suggesting a dominant terrestrial origin of CDOM. On the contrary, samples collected in the marine domain showed a narrow range of aCDOM(375) but highly variable S suggesting the additional presence of autochthonous sources of CDOM. This source was evidenced based on the sorting of the marine offshore data according to the stage of the phytoplankton bloom when they were collected. A clear distinction was made between CDOM released during the growth stage characterized by high S (∼0.017 nm-1) and low aCDOM(375) and the decay phase characterized by low S (∼0.013 nm-1) and high aCDOM(375). This observation was supported by CDOM measurements performed on pure phytoplankton cultures which showed increased CDOM release along the wax and wane of the bloom but decreasing S. We concluded that the high variability of the CDOM signature in offshore waters is explained by the local biological production and processing of CDOM. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{AstorecaRousseauLancelot2009,
  author = {Astoreca, R. and Rousseau, V. and Lancelot, C.},
  title = {Coloured dissolved organic matter (CDOM) in Southern North Sea waters: Optical characterization and possible origin},
  journal = {Estuarine, Coastal and Shelf Science},
  year = {2009},
  volume = {85},
  pages = {633-640},
  doi = {10.1016/j.ecss.2009.10.010}
}
Abstract: Chlorophyll a retrieval from satellite is based on algorithms that convert the phytoplankton absorption into chlorophyll a by means of the specificphytoplankton absorption. This factor has been found to be highly variable, spatially and seasonally. The variability of the chlorophyll a-specific phytoplankton absorption in Belgian waters (Southern North Sea) was investigated to determine how it is affecting the chlorophyll a retrieval from satellite information. The Southern Bight of the North Sea is a very dynamic area influenced by river discharges and characterised by highly variable chlorophyll, suspended matter and coloured dissolved organic matter absorption. The impact of using a mean value of specificphytoplankton absorption as usually done instead of the real one in chlorophyll a retrieval was estimated and found to be significant (underestimation up to 70% at 665 nm).
BibTeX:
@conference{AstorecaRousseauLancelot2006,
  author = {Astoreca, R. and Rousseau, V. and Lancelot, C.},
  title = {Specific phytoplankton absorption variability and implication for chlorophyll a retrieval in Belgian waters (Southern North Sea)},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2006}
}
Abstract: While mapping algal blooms from space is now well-established, mapping undesirable algal blooms in eutrophicated coastal waters raises further challenge in detecting individual phytoplankton species. In this paper, an algorithm is developed and tested for detecting Phaeocystis globosa blooms in the Southern North Sea. For this purpose, we first measured the light absorption properties of two phytoplankton groups, P. globosa and diatoms, in laboratory-controlled experiments. The main spectral difference between both groups was observed at 467 nm due to the absorption of the pigment chlorophyll c3 only present in P. globosa, suggesting that the absorption at 467 nm can be used to detect this alga in the field. A Phaeocystis-detection algorithm is proposed to retrieve chlorophyll c3 using either total absorption or water-leaving reflectance field data. Application of this algorithm to absorption and reflectance data from Phaeocystis-dominated natural communities shows positive results. Comparison with pigment concentrations and cell counts suggests that the algorithm can flag the presence of P. globosa and provide quantitative information above a chlorophyll c3 threshold of 0.3 mg m -3 equivalent to a P. globosa cell density of 3 × 10 6 cells L-1. Finally, the possibility of extrapolating this information to remote sensing reflectance data in these turbid waters is evaluated. © 2008 The Author(s).
BibTeX:
@article{AstorecaRousseauRuddickEtAl2009,
  author = {Astoreca, R. and Rousseau, V. and Ruddick, K. and Knechciak, C. and Van Mol, B. and Parent, J.-Y. and Lancelot, C.},
  title = {Development and application of an algorithm for detecting Phaeocystis globosa blooms in the Case 2 Southern North Sea waters},
  journal = {Journal of Plankton Research},
  year = {2009},
  volume = {31},
  pages = {287-300},
  doi = {10.1093/plankt/fbn116}
}
Abstract: The Southern Bight of the North Sea is characterised by a large influence of river inputs, which results in eutrophication of the area. High concentrations of plankton biomass and suspended matter have been reported for this area, in relation with blooms of different species and resuspension of bottom sediments. In spring the haptophyte Phaeocystis globosa blooms throughout the area reaching up to 30 mg Chlorophyll m-3 or more nearshore. This event is followed in June by red tides of the dinoflagellate Noctiluca scintillans. These blooms are concurrent with different species of diatoms. The strong optical signature of these blooms is clear to human observers making them potentially detectable in satellite imagery. As a first step in this direction, sampling has been carried out in the area, during Phaeocystis and Noctiluca blooms in 2003 and 2004. Phytoplankton pigments and inherent optical properties (particle, detrital and phytoplankton absorption) have been measured spectrophotometrically, and in situ using an ac-9 for total absorption and particle scattering. Field data were compared with optical properties of pure species obtained in laboratory. In parallel, water-leaving reflectance has been also measured. In this paper we characterise the optical signatures of diatoms, Phaeocystis and Noctiluca and their contribution to total absorption. The impact on water-leaving reflectance spectra is evaluated; in order to assess the conditions in which remote sensing can provide information for monitoring the timing, extent and magnitude of blooms in this coastal area.
BibTeX:
@conference{AstorecaRousseauRuddickEtAl2005,
  author = {Astoreca, R. and Rousseau, V. and Ruddick, K. and Van Mol, B. and Parent, J.-Y. and Lancelot, C.},
  title = {Optical properties of algal blooms in an eutrophicated coastal area and its relevance to remote sensing},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2005},
  volume = {5885},
  article number = {58850V},
  pages = {1-11},
  doi = {10.1117/12.615160}
}
Abstract: Absolute line intensities of 13C16O2 were retrieved from high-resolution Fourier transform spectra recorded in the region 3090-3920 cm-1. The uncertainty of the line intensity determination is estimated to be between 3 and 5% for the strong lines. The global fittings of the observed line intensities within the framework of the effective operators approach have been performed, reaching the experimental accuracy. A comparison of newly measured line intensities with those found in the HITRAN database is presented. © 2005 Elsevier Inc. All rights reserved.
BibTeX:
@article{AuweraClaveauTeffoEtAl2006,
  author = {Auwera, J.V. and Claveau, C. and Teffo, J.-L. and Tashkun, S.A. and Perevalov, V.I.},
  title = {Absolute line intensities of 13C16O2 in the 3090-3920 cm-1 region},
  journal = {Journal of Molecular Spectroscopy},
  year = {2006},
  volume = {235},
  pages = {77-83},
  doi = {10.1016/j.jms.2005.10.005}
}
Abstract: The prediction and observation of an infrared optical double resonance scheme in glyoxal is reported. © 1987.
BibTeX:
@article{AuweraHerman1987,
  author = {Auwera, J.V. and Herman, M.},
  title = {Infrared optical double resonance signal in glyoxal (C2H2O2)},
  journal = {Chemical Physics Letters},
  year = {1987},
  volume = {135},
  pages = {432-434},
  doi = {10.1016/0009-2614(87)85184-9}
}
Abstract: The infrared spectrum of the ν6 band system of carbon suboxide, C3O2, has been recorded between 500 and 600 cm-1 at a resolution of 0.002 cm-1. Altogether 23 bands have been assigned. They correspond to transitions ν6 + nν7 ← nν7, n ≤ 9, where ν6 is the asymmetric CCO bending mode and ν7 is the very anharmonic CCC bending mode. Among these bands, 20 have been rotationally analyzed and 1220 lines assigned. The line positions were fitted to effective parameters which characterize these 20 vibrational levels in the ν6 state. The results of the fits were then fitted so a semirigid bender model in order to determine the effective CCC bending potential function in the ν6 state. © 1994 Academic Press, Inc.
BibTeX:
@article{AuweraHollandJensenEtAl1994,
  author = {Auwera, J. and Holland, J.K. and Jensen, P. and Johns, J.W.C.},
  title = {The ν6 band system of c3o2 near 540 cm-11},
  journal = {Journal of Molecular Spectroscopy},
  year = {1994},
  volume = {163},
  pages = {529-540},
  doi = {10.1006/jmsp.1994.1045}
}
Abstract: The semiclassical formalism of Robert and Bonamy is used to calculate the linewidths of rovibrational transitions of ammonia in collision with argon. Two accurate ab initio potential energy surfaces (PES) have been applied to model the NH3-Ar interactions. In this work and contrary to our previous calculations, the transitions with ΔK = ±3n (n integer) have been introduced into the expressions of the differential collision cross section S(b). Comparisons with previous theoretical and experimental studies are reported. A detailed analysis of the contribution of the various anisotropic components of the PES shows that the induced ΔK = ±3 transitions play a crucial role. Calculations performed in the ν4 and ν1 vibrational bands of NH3 are in good agreement with the experimental data and correct dependences of the broadening coefficients with the rotational quantum numbers J and K are obtained. © 2015 Published by Elsevier Inc.
BibTeX:
@article{AyariLoreauDhibEtAl2015,
  author = {Ayari, C. and Loreau, J. and Dhib, M. and Daussy, C. and Aroui, H.},
  title = {Semiclassical line broadening calculations using an ab initio potential. Application to NH3 perturbed by argon},
  journal = {Journal of Molecular Spectroscopy},
  year = {2015},
  volume = {318},
  pages = {46-52},
  doi = {10.1016/j.jms.2015.09.011}
}
Abstract: The development of experimental ion-trap techniques provides the opportunity to compare directly theoretical rate coefficients to experimental data in the low-temperature regime. In the present work, we consider the ion-atom collisional systems, N2+, O2+, Si3+ and Si4+ on a He target, in order to examine the present status of the agreement between theory and experiment.
BibTeX:
@article{Bacchus-MontabonelBaloitchaDesouter-LecomteEtAl2002,
  author = {Bacchus-Montabonel, M.-C. and Baloïtcha, E. and Desouter-Lecomte, M. and Vaeck, N.},
  title = {Rate coefficient determination in charge transfer reactions},
  journal = {International Journal of Molecular Sciences},
  year = {2002},
  volume = {3},
  pages = {176-189},
  doi = {10.3390/i3030176}
}
Abstract: The competitive photodissociation of bromoacetyl chloride has been investigated by means of ab initio methods. Quantum dynamics in full dimensionality is prohibitive for such a system and therefore a reduced dimensionality method based on constrained Hamiltonians has been used. A one-dimensional (1-D) non-adiabatic wave packet treatment in the CS optimized geometry (trans Cl and Br) on the first excited states leads to encouraging results when compared to experimental data. The slow relaxation of the torsion angle is assessed by a 2-D dynamics in the subspace including the C=O bond length. © 2003 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{Bacchus-MontabonelVaeckLasorneEtAl2003,
  author = {Bacchus-Montabonel, M.-C. and Vaeck, N. and Lasorne, B. and Desouter-Lecomte, M.},
  title = {Non-adiabatic effects in the photodissociation of bromoacetyl chloride},
  journal = {Chemical Physics Letters},
  year = {2003},
  volume = {374},
  pages = {307-313},
  doi = {10.1016/S0009-2614(03)00606-7}
}
Abstract: This work presents new measurements of HDO line parameters in the near-infrared and visible regions (11 500-23 000 cm-1). The measurements consist in high-resolution Fourier transform absorption spectra of H2O/HDO/D2O vapor mixtures, obtained using a long absorption path. Spectra with and without nitrogen as the buffer gas were recorded. Due to the simultaneous presence of the three isotopologues H 2O, D2O, and HDO, the H2O lines removal and the D2O lines identification were two necessary preliminary steps to derive the HDO line parameters. The D2O contribution was small and confined to the well-known 4ν1 + ν3 band. An extensive listing of HDO spectroscopic parameters was obtained, for the first time, by fitting some 3256 observed lines to Voigt line profiles. The list contains calibrated line positions, absorption cross-sections and, for many of the lines, N2-broadening coefficients, as well as N 2-induced frequency shifts. As a result of the low HDO vapor pressures, it was not possible to retrieve the self-broadening parameters. The list is available on the http://www.ulb.ac.be/cpm website. © 2005 Elsevier Inc. All rights reserved.
BibTeX:
@article{BachFallyCoheurEtAl2005,
  author = {Bach, M. and Fally, S. and Coheur, P.-F. and Carleer, M. and Jenouvrier, A. and Vandaele, A.C.},
  title = {Line parameters of HDO from high-resolution Fourier transform spectroscopy in the 11 500-23 000 cm-1 spectral region},
  journal = {Journal of Molecular Spectroscopy},
  year = {2005},
  volume = {232},
  pages = {341-350},
  doi = {10.1016/j.jms.2005.04.018}
}
Abstract: A Fourier transform interferometer was used to record the slit-jet absorption spectrum of 12C2H4 between 2500 and 3500 cm-1 at a spectral resolution of 0.02 cm-1. The rotational analysis of the ν9 and ν11 fundamental and ν2+ν12 combination bands is performed, effective rotational parameters are presented, and relative absorption intensities are measured. In addition, a few lines of the 2ν10+ν12 band are assigned. The selective sampling of vibrational hot bands in the jet is demonstrated using another experimental apparatus, with a heated slit.
BibTeX:
@article{BachGeorgesHeppEtAl1998,
  author = {Bach, M. and Georges, R. and Hepp, M. and Herman, M.},
  title = {Slit-jet Fourier transform infrared spectroscopy in 12C2H4 : Cold and hot bands near 3000 cm-1},
  journal = {Chemical Physics Letters},
  year = {1998},
  volume = {294},
  pages = {533-537},
  doi = {10.1016/S0009-2614(98)00889-6}
}
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled overtone absorption spectrum of 12C2H4 between 3900 and 7900cm−1, at a spectral resolution of 0.02cm−1 and a rotational temperature of 53 K. Some 17 bands were observed and rotationally analysed, leading to effective vibration—rotation constants for all upper states. Coriolis perturbations were identified and refined vibration—rotation constants were produced for seven upper states as well as for 12 Coriolis interacting dark states. Symmetry conventions different from those of the previous literature are selected in the present work. © 1999 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{BachGeorgesHermanEtAl1999,
  author = {Bach, M. and Georges, R. and Herman, M. and Perrin, A.},
  title = {Investigation of the fine structure in overtone absorption bands of 12C2H4},
  journal = {Molecular Physics},
  year = {1999},
  volume = {97},
  pages = {265-277},
  doi = {10.1080/00268979909482828}
}
Abstract: Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this study, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5° N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected &upsilon;8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximise the information content. Methanol does not exhibit a significant trend over the 1995-2012 time period, but a strong seasonal modulation characterised by maximum values and variability in June-July, minimum columns in winter and a peak-to-peak amplitude of 130%. Analysis and comparisons with in situ measurements carried out at the Jungfraujoch and ACE-FTS (Atmospheric Chemistry Experiment-Fourier transform spectrometer) occultations have been performed. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations.
BibTeX:
@article{BaderStavrakouMullerEtAl2014,
  author = {Bader, W. and Stavrakou, T. and Muller, J.-F. and Reimann, S. and Boone, C.D. and Harrison, J.J. and Flock, O. and Bovy, B. and Franco, B. and Lejeune, B. and Servais, C. and Mahieu, E.},
  title = {Long-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5° N, 8.0° E): Optimisation of the retrieval strategy, comparison with model simulations and independent observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {3861-3872},
  doi = {10.5194/amt-7-3861-2014}
}
Abstract: Results of calculations using a configuration interaction LCAO-MO method are presented for the X 2Σ+ and A 2∏ states of BeH. Apart from the 1s shell of Be, the correlation energy of the remaining three electrons is calculated quantitatively using an extended basis set and complete configuration interaction including all single, double and triple replacements. The calculated spectroscopic constants are in excellent agreement with available experimental data. The present calculations also predict a value of De(BeH, X 2Σ+) = 2.115 eV, and dismiss the possibility of a potential maximum in the ground state potential energy curve.
BibTeX:
@article{BagusMoserGoethalsEtAl1973,
  author = {Bagus, P.S. and Moser, C.M. and Goethals, P. and Verhaegen, G.},
  title = {Accurate ab initia calculation of the BeH molecule. I. the X 2Σ+ and A2∏ states},
  journal = {The Journal of Chemical Physics},
  year = {1973},
  volume = {58},
  pages = {1886-1897},
  doi = {10.1063/1.1679448}
}
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF-ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate. © Author(s) 2015.
BibTeX:
@article{BaldassarrePozzoliSchmidtEtAl2015,
  author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.},
  title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: A case study over Antalya in 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8539-8558},
  doi = {10.5194/acp-15-8539-2015}
}
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on fire gaseous and aerosol emissions for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a unique temporal resolution of 15min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in MODIS-based fire emission inventories like GFAS. We evaluate two different operational Fire Radiative Power (FRP) products derived from SEVIRI, by studying the case of a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT LSA SAF product has higher FRP values during the fire episode than the WF-ABBA product. It is also in better agreement with the colocated, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with WRF and the Community Multiscale Air Quality model (CMAQ). Comparisons with MODIS AOT and IASI CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated to the large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF one being the most appropriate. � Author(s) 2015. CC Attribution 3.0 License.
BibTeX:
@article{BaldassarrePozzoliSchmidtEtAl2015a,
  author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.},
  title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: The case of Antalya in 2008},
  journal = {Atmospheric Chemistry and Physics Discussions},
  year = {2015},
  volume = {15},
  pages = {1-46},
  doi = {10.5194/acpd-15-1-2015}
}
Abstract: The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the ĝ zero tolerance to ashĝ€ rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and height extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash layer height when compared with the ground-based and airborne lidar data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{BalisKoukouliSiomosEtAl2016,
  author = {Balis, D. and Koukouli, M.-E. and Siomos, N. and Dimopoulos, S. and Mona, L. and Pappalardo, G. and Marenco, F. and Clarisse, L. and J Ventress, L. and Carboni, E. and G Grainger, R. and Wang, P. and Tilstra, G. and Van Der A, R. and Theys, N. and Zehner, C.},
  title = {Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {5705-5720},
  doi = {10.5194/acp-16-5705-2016}
}
Abstract: The 2010 eruptions of the Icelandic volcano Eyjafjallajokull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. The European Space Agency project "Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards", called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation, using among others ground-based measurements (Koukouli et al., 2014). The validation of volcanic ash levels and height extracted from IASI/MetopA is presented in this work with emphasis on the ash plume height and ash optical depth levels. European Aerosol Research Lidar Network [EARLINET] lidar measurements are compared to different satellite estimates for two eruptive episodes. The validation results are extremely promising within the estimated uncertainties of each of the comparative datasets. © 2016 Owned by the authors, published by EDP Sciences.
BibTeX:
@conference{BalisSiomosKoukouliEtAl2016,
  author = {Balis, D. and Siomos, N. and Koukouli, M. and Clarisse, L. and Carboni, E. and Ventress, L. and Grainger, R. and Mona, L. and Pappalardo, G.},
  title = {Validation of ASH Optical Depth and Layer Height from IASI using Earlinet Lidar Data},
  journal = {EPJ Web of Conferences},
  year = {2016},
  volume = {119},
  article number = {07006},
  doi = {10.1051/epjconf/201611907006}
}
Abstract: An intercomparison of measurements of infra-red absorption cross-sections and integrated absorption intensities in HCFC-22 has been carried out. Independent measurements were made by five spectroscopy groups so that their experimental methods and data reduction techniques could be critically examined. The initial results showed a spread in reported values for integrated absorption intensity over the mid infra-red spectral region that were larger than the reported uncertainties. Re-examination of experimental and data reduction methods resulted in consistency of results within the reported errors. It was found that particular attention had to be paid to controlling and characterising errors associated with the non-linear response of MCT detectors and pre-amplifiers, adsorption of the sample on surfaces in the absorption cell, effectiveness of mixing when making measurements on mixtures of absorber gas and a buffer gas, and location of the photometric "full-scale" and "zero" levels. © 2000 Elsevier Science Ltd. All rights reserved.
BibTeX:
@article{BallardKnightNewnhamEtAl2000,
  author = {Ballard, J. and Knight, R.J. and Newnham, D.A. and Vander Auwera, J. and Herman, M. and Di Lonardo, G. and Masciarelli, G. and Nicolaisen, F.M. and Beukes, J.A. and Christensen, L.K. and McPheat, R. and Duxbury, G. and Freckleton, R. and Shine, K.P.},
  title = {An intercomparison of laboratory measurements of absorption cross-sections and integrated absorption intensities for HCFC-22},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2000},
  volume = {66},
  pages = {109-128},
  doi = {10.1016/S0022-4073(99)00211-3}
}
Abstract: Efficiency of different time-dependent and time-independent wave packet methods for charge-exchange cross sections in ion-atom collisions was discussed. The time-independent spectral projection method, based on the Chebyshev expansion of the resolvent function involved a time propagation while the flux operator method required propagation in time. Flux operator method used the properties of absorbing potentials in order to calculate the flux operator matrix elements.
BibTeX:
@article{BaloitchaDesouter-LecomteBacchus-MontabonelEtAl2001,
  author = {Baloïtcha, E. and Desouter-Lecomte, M. and Bacchus-Montabonel, M.-C. and Vaeck, N.},
  title = {Wave packet methods for charge exchange processes in ion-atom collisions},
  journal = {Journal of Chemical Physics},
  year = {2001},
  volume = {114},
  pages = {8741-8751},
  doi = {10.1063/1.1367378}
}
Abstract: The assessment of changes induced by human activities on Earth atmospheric composition and thus on global climate requires a long-term and regular survey of the stratospheric and tropospheric atmospheric layers. The objective of this paper is to describe the atmospheric observations performed continuously at Reunion Island (55.5°east, 20.8°south) for 15 years. The various instruments contributing to the systematic observations are described as well as the measured parameters, the accuracy and the database. The LiDAR systems give profiles of temperature, aerosols and ozone in the troposphere and stratosphere, probes give profiles of temperature, ozone and relative humidity, radiometers and spectrometers give stratospheric and tropospheric integrated columns of a variety of atmospheric trace gases. Data are included in international networks, and used for satellite validation. Moreover, some scientific activities for which this station offers exceptional opportunities are highlighted, especially air mass exchanges nearby dynamical barriers: (1) On the vertical scale through the tropical tropopause layer (stratosphere-troposphere exchange). (2) On the quasi-horizontal scale across the southern subtropical barrier separating the tropical stratospheric reservoir from mid- and high latitudes. © The Royal Society of Chemistry 2006.
BibTeX:
@article{BarayLeveauBaldyEtAl2006,
  author = {Baray, J.-L. and Leveau, J. and Baldy, S. and Jouzel, J. and Keckhut, P. and Bergametti, G. and Ancellet, G. and Bencherif, H. and Cadet, B. and Carleer, M. and David, C. and De Mazière, M. and Faduilhe, D. and Godin Beekmann, S. and Goloub, P. and Goutail, F. and Metzger, J.M. and Morel, B. and Pommereau, J.P. and Porteneuve, J. and Portafaix, T. and Posny, F. and Robert, L. and Van Roozendael, M.},
  title = {An instrumented station for the survey of ozone and climate change in the southern tropics},
  journal = {Journal of Environmental Monitoring},
  year = {2006},
  volume = {8},
  pages = {1020-1028},
  doi = {10.1039/b607762e}
}
Abstract: Most satellite models of production have been designed and calibrated for use in the open ocean. Coastal waters are optically more complex, and the use of chlorophyll a (chl a) as a first-order predictor of primary production may lead to substantial errors due to significant quantities of coloured dissolved organic matter (CDOM) and total suspended material (TSM) within the first optical depth. We demonstrate the use of phytoplankton absorption as a proxy to estimate primary production in the coastal waters of the North Sea and Western English Channel for both total, micro- and nano+pico-phytoplankton production. The method is implemented to extrapolate the absorption coefficient of phytoplankton and production at the sea surface to depth to give integrated fields of total and micro- and nano+pico-phytoplankton primary production using the peak in absorption coefficient at red wavelengths. The model is accurate to 8% in the Western English Channel and 22% in this region and the North Sea. By comparison, the accuracy of similar chl a based production models was >250%. The applicability of the method to autonomous optical sensors and remotely sensed aircraft data in both coastal and estuarine environments is discussed. © Inter-Research 2014.
BibTeX:
@article{BarnesTilstoneSmythEtAl2014,
  author = {Barnes, M.K. and Tilstone, G.H. and Smyth, T.J. and Suggett, D.J. and Astoreca, R. and Lancelot, C. and Kromkamp, J.C.},
  title = {Absorption-based algorithm of primary production for total and size-fractionated phytoplankton in coastal waters},
  journal = {Marine Ecology Progress Series},
  year = {2014},
  volume = {504},
  pages = {73-89},
  doi = {10.3354/meps10751}
}
Abstract: We show the results and evaluation with independent measurements from assimilating both MOPITT (Measurements Of Pollution In The Troposphere) and IASI (Infrared Atmospheric Sounding Interferometer) retrieved profiles into the Community Earth System Model (CESM). We used the Data Assimilation Research Testbed ensemble Kalman filter technique, with the full atmospheric chemistry CESM component Community Atmospheric Model with Chemistry. We first discuss the methodology and evaluation of the current data assimilation system with coupled meteorology and chemistry data assimilation. The different capabilities of MOPITT and IASI retrievals are highlighted, with particular attention to instrument vertical sensitivity and coverage and how these impact the analyses. MOPITT and IASI CO retrievals mostly constrain the CO fields close to the main anthropogenic, biogenic, and biomass burning CO sources. In the case of IASI CO assimilation, we also observe constraints on CO far from the sources. During the simulation time period (June and July 2008), CO assimilation of both instruments strongly improves the atmospheric CO state as compared to independent observations, with the higher spatial coverage of IASI providing better results on the global scale. However, the enhanced sensitivity of multispectral MOPITT observations to near surface CO over the main source regions provides synergistic effects at regional scales. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BarreGaubertArellanoEtAl2015,
  author = {Barré, J. and Gaubert, B. and Arellano, A.F.J. and Worden, H.M. and Edwards, D.P. and Deeter, M.N. and Anderson, J.L. and Raeder, K. and Collins, N. and Tilmes, S. and Francis, G. and Clerbaux, C. and Emmons, L.K. and Pfister, G.G. and Coheur, P.-F. and Hurtmans, D.},
  title = {Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART},
  journal = {Journal of Geophysical Research},
  year = {2015},
  volume = {120},
  pages = {10501-10529},
  doi = {10.1002/2015JD023467}
}
Abstract: Collision-induced line narrowing, which has been discovered in the 1950s and investigated thoroughly in the laboratory since then, has yet never been taken into account in the spectroscopic remote sensing of the atmosphere. This work investigates the effect of collision-induced line narrowing onto the retrieval of HCl and HF vertical profiles from ground-based solar absorption FTIR measurements made at the NDSC station of the Jungfraujoch (46.5°N, 8°E and 3580 m above see level). The retrievals are performed with the Atmosphit software, recently developed at the Université Libre de Bruxelles. It is presented in this paper for the first time and is validated against the widely used SFIT2 software. The impact of the line narrowing onto the retrieval of HCl and HF vertical profiles is examined relying on careful information content and error budget analyses. We report that the effect is relatively weak for HCl but significant for HF. Confirmation of the need to take the line narrowing into account for the retrieval of vertical profiles from ground-based FTIR spectra is given by comparison with data from the HALOE space borne instrument, rather insensitive to this spectroscopic effect. © 2005 Elsevier Ltd. All rights reserved.
BibTeX:
@article{BarretHurtmansCarleerEtAl2005,
  author = {Barret, B. and Hurtmans, D. and Carleer, M.R. and De Mazière, M. and Mahieu, E. and Coheur, P.-F.},
  title = {Line narrowing effect on the retrieval of HF and HCl vertical profiles from ground-based FTIR measurements},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2005},
  volume = {95},
  pages = {499-519},
  doi = {10.1016/j.jqsrt.2004.12.005}
}
Abstract: In order to better understand the chemistry and the transport mechanisms in the lower troposphere, a new original technique has been developed and tested. The experiment consists in recording high resolution infrared solar absorption spectra containing signatures of important atmospheric constituents, simultaneously from the International Scientific Station of the Jungfraujoch in Switzerland (ISSJ, 3580 m a.s.l., 46.5°N, 8°E, Bruker 120HR Fourier transform spectrometer (FTS)) and from a nearby valley (Grindelwald, 1070 m a.s.l., Bruker 120M FTS). Analysis of individual spectra allows to determine vertical column abundances; differences between measurements at ISSJ and at Grindelwald enable us to retrieve the constituents' concentrations between 1070 m and 3580 m, assuming a constant volume mixing ratio in this layer. A first measurement campaign has been organized during the months of May and June 1998. After an initial period of instrument intercomparison at ISSJ, the mobile instrument was moved down in the valley and installed for one month in Grindelwald. When operated side by side at the Jungfraujoch, measurements made by both instruments showed a very good agreement (maximum bias of 1.5%). Analysis of spectra recorded synchronously at the Jungfraujoch and at Grindelwald gave average boundary layer concentrations for a selected set of tropospheric molecules, i.e. methane, nitrous oxide, carbon monoxide and ethane. Comparison with other results and with carbon monoxide in-situ measurements made at ISSJ showed a good agreement.
BibTeX:
@conference{BarretMahieuCarleerEtAl1999,
  author = {Barret, Brice and Mahieu, Emmanuel and Carleer, Michel and De Maziere, Martine and Colin, Reginald and Zander, Rodolphe},
  title = {Tropospheric boundary layer investigations by differential ground-based solar FTIR spectrometry},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {1999},
  volume = {3821},
  pages = {116-123}
}
Abstract: This paper presents the first global distributions of CO vertical profiles retrieved from a thermal infrared FTS working in the nadir geometry. It is based on the exploitation of the high resolution and high quality spectra measured by the Interferometric Monitor of Greenhouse gases (IMG) which flew onboard the Japanese ADEOS platform in 1996-1997. The retrievals are performed with an algorithm based on the Optimal Estimation Method (OEM) and are characterized in terms of vertical sensitivity and error budget. It is found that most of the IMG measurements contain between 1.5 and 2.2 independent pieces of information about the vertical distribution of CO from the lower troposphere to the upper troposphere-lower stratosphere (UTLS). The retrievals are validated against coincident NOAA/CMDL in situ surface measurements and NDSC/FTIR total columns measurements. The retrieved global distributions of CO are also found to be in good agreement with the distributions modeled by the GEOS-CHEM 3D CTM, highlighting the ability of IMG to capture the horizontal as well as the vertical structure of the CO distribution. © 2005 Author(s). This work is licensed under a Creative Commons License.
BibTeX:
@article{BarretTurquetyHurtmansEtAl2005,
  author = {Barret, B. and Turquety, S. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Bey, I. and Auvray, M. and Coheur, P.-F.},
  title = {Global carbon monoxide vertical distributions from spaceborne high-resolution FTIR nadir measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2005},
  volume = {5},
  pages = {2901-2914},
  doi = {10.5194/acp-5-2901-2005}
}
Abstract: The rate constant for the reaction of the hydroxyl radical with 1,1,1,3,3-pentafluorobutane (HFC-365mfc) has been determined over the temperature range 278-323 K using a relative rate technique. The results provide a value of k(OH + CF3CH2CF2CH3) = 2.0 × 10-12 exp(- 1750 ± 400/T) cm3 molecule-1 s-1 based on k(OH + CH3CCl3) = 1.8 × 10-12 exp (- 1550 ± 150/T) cm3 molecule-1 s-1 for the rate constant of the reference reaction. Assuming the major atmospheric removal process is via reaction with OH in the troposphere, the rate constant data from this work gives an estimate of 10.8 years for the tropospheric lifetime of HFC-365mfc. The overall atmospheric lifetime obtained by taking into account a minor contribution from degradation in the stratosphere, is estimated to be 10.2 years. The rate constant for the reaction of Cl atoms with 1,1,1,3,3-pentafluorobutane was also determined at 298 ± 2 K using the relative rate method, k(Cl + CF3CH2CF2CH3) = (1.1 ± 0.3) × 10-15 cm3 molecule-1 s-1. The chlorine initiated photooxidation of CF3CH2CF2CH3 was investigated from 273-330 K and as a function of O2 pressure at 1 atmosphere total pressure using Fourier transform infrared spectroscopy. Under all conditions the major carbon-containing products were CF2O and CO2, with smaller amounts of CF3O3CF3. In order to ascertain the relative importance of hydrogen abstraction from the - CH2 - and - CH3 groups in CF3CH2CF2CH3, rate constants for the reaction of OH radicals and Cl atoms with the structurally similar compounds CF3CH2CCl2F and CF3CH2CF3 were also determined at 298 K k(OH + CF3CH2CCl2F) = (8 ± 3) × 10-16 cm3 molecule-1 s-1; k(OH + CF3CH2CF3) = (3.5 ± 1.5) × 10-16 cm3 molecule-1 s-1; k(Cl + CF3CH2CCl2F) = (3.5 ± 1.5) × 10-17 cm3 molecule-1 s-1; k(C; + CF3CH2F3) &lt; 1 × 10-17 cm3 molecule-1 s-1. The results indicate that the most probable site for H-atom abstraction from CF3CH2CF2CH3 is the methyl group and that the formation of carbonyl compounds containing more than a single carbon atom will be negligible under atmospheric conditions, carbonyl difluoride and carbon dioxide being the main degradation products. Finally, accurate infrared absorption cross-sections have been measured for CF3CH2CF2CH3, and jointly used with the calculated overall atmospheric lifetime of 10.2 years, in the NCAR chemical-radiative model, to determine the radiative forcing of climate by this CFC alternative. The steady-state Halocarbon Global Warming Potential, relative to CFC-11, is 0.17. The Global Warming Potentials relative to CO2 are found to be 2210, 790, and 250, for integration time-horizons of 20, 100, and 500 years, respectively. © 1997 John Wiley &amp; Sons, Inc.
BibTeX:
@article{BarryLockeScollardEtAl1997,
  author = {Barry, J. and Locke, G. and Scollard, D. and Sidebottom, H. and Treacy, J. and Clerbaux, C. and Colin, R. and Franklin, J.},
  title = {1,1,1,3,3,-pentafluorobutane (HFC-365mfc): Atmospheric degradation and contribution to radiative forcing},
  journal = {International Journal of Chemical Kinetics},
  year = {1997},
  volume = {29},
  pages = {607-617},
  doi = {10.1002/(SICI)1097-4601(1997)29:8<607::AID-KIN6>3.0.CO;2-Y}
}
Abstract: Nonempirical molecular structure calculations were performed to obtain an electronic potential energy surface for the CH2+ radical. The vibrational Eckart Hamiltonian was approximately solved on this surface using a variational method, with basis functions designed to allow for the singular behavior of the Eckart Hamiltonian as the radical becomes linear. © 1981.
BibTeX:
@article{BartholomaeMartinSutcliffe1981,
  author = {Bartholomae, R. and Martin, D. and Sutcliffe, B.T.},
  title = {A nonempirical calculation of the lowest vibrational band origins for the CH2+ radical using a novel vibrational wavefunction},
  journal = {Journal of Molecular Spectroscopy},
  year = {1981},
  volume = {87},
  pages = {367-381},
  doi = {10.1016/0022-2852(81)90409-4}
}
Abstract: We solve the entanglement classification under stochastic local operations and classical communication (SLOCC) for all multipartite symmetric states in the general N-qubit case. For this purpose, we introduce 2 parameters playing a crucial role, namely, the diversity degree and the degeneracy configuration of a symmetric state. Those parameters give rise to a simple method of identifying operational families of SLOCC entanglement classes of all symmetric N-qubit states, where the number of families grows as the partition function of the number of qubits. © 2009 The American Physical Society.
BibTeX:
@article{BastinKrinsMathonetEtAl2009,
  author = {Bastin, T. and Krins, S. and Mathonet, P. and Godefroid, M. and Lamata, L. and Solano, E.},
  title = {Operational families of entanglement classes for symmetric N-qubit states},
  journal = {Physical Review Letters},
  year = {2009},
  volume = {103},
  article number = {070503},
  doi = {10.1103/PhysRevLett.103.070503}
}
Abstract: We estimate the CO2 flux over Tropical Asia in 2009, 2010, and 2011 using Greenhouse Gases Observing Satellite (GOSAT) total column CO 2(XCO2) and in situ measurements of CO2. Compared to flux estimates from assimilating surface measurements of CO 2, GOSAT XCO2 estimates a more dynamic seasonal cycle and a large source in March-May 2010. The more dynamic seasonal cycle is consistent with earlier work by Patra et al. (2011), and the enhanced 2010 source is supported by independent upper air CO2 measurements from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. Using Infrared Atmospheric Sounding Interferometer (IASI) measurements of total column CO (XCO), we show that biomass burning CO2 can explain neither the dynamic seasonal cycle nor the 2010 source. We conclude that both features must come from the terrestrial biosphere. In particular, the 2010 source points to biosphere response to above-average temperatures that year. Key Points GOSAT estimates a dynamic seasonal cycle over Tropical Asia The GOSAT-estimated seasonal cycle is confirmed by CONTRAIL data IASI CO shows that the dynamism is not caused by biomass burning ©2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BasuKrolButzEtAl2014,
  author = {Basu, S. and Krol, M. and Butz, A. and Clerbaux, C. and Sawa, Y. and Machida, T. and Matsueda, H. and Frankenberg, C. and Hasekamp, O.P. and Aben, I.},
  title = {The seasonal variation of the CO2 flux over Tropical Asia estimated from GOSAT, CONTRAIL, and IASI},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {1809-1815},
  doi = {10.1002/2013GL059105}
}
Abstract: Norilsk is one of the most polluted cities in the world, largely because of intense mining of heavy metals. Here we present satellite observations of SO2 in a large area surrounding the city, derived from 4 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI), the nadir thermal infrared (TIR) sounder onboard the MetOp platforms. TIR instruments are conventionally considered to be inadequate for monitoring near-surface composition, because their sensitivity to the lowest part of the atmosphere is limited by the thermal contrast between the ground and the air above it. We demonstrate that IASI is capable of measuring SO2 (here as a partial column from 0 to 2 km) in Norilsk, thanks to the large temperature inversions and the low humidity in wintertime. We discuss the influence of thermal contrast and of surface humidity on the SO2 retrieved columns and estimate the retrieval errors. Using a simple box model, we derive the yearly total emissions of SO2 from Norilsk and compare them to previously reported values. More generally, we present in this work the first large-scale demonstration of the capability of space-based TIR sounders to measure near-surface SO2 anthropogenic pollution. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BauduinClarisseClerbauxEtAl2014,
  author = {Bauduin, S. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk},
  journal = {Journal of Geophysical Research},
  year = {2014},
  volume = {119},
  pages = {4253-4263},
  doi = {10.1002/2013JD021405}
}
Abstract: SO2 from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows the peak altitude of SO2 to be retrieved and near-surface SO2 to be selected. In the second step, 0-4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to nearsurface SO2 in the ν3 band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0-4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI). © Author(s) 2016.
BibTeX:
@article{BauduinClarisseHadji-LazaroEtAl2016,
  author = {Bauduin, S. and Clarisse, L. and Hadji-Lazaro, J. and Theys, N. and Clerbaux, C. and Coheur, P.-F.},
  title = {Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {721-740},
  doi = {10.5194/amt-9-721-2016}
}
Abstract: Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements. © 2017 Elsevier Ltd
BibTeX:
@article{BauduinClarisseTheunissenEtAl2017,
  author = {Bauduin, S. and Clarisse, L. and Theunissen, M. and George, M. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {189},
  pages = {428-440},
  doi = {10.1016/j.jqsrt.2016.12.022}
}
Abstract: Since its first measurement 20 years ago by the Infrared Space Observatory (ISO), the water (H2O) mole fraction in Titan's stratosphere remains uncertain due to large differences between the determinations from available measurements. More particularly, the recent measurements made from the Herschel observatory (PACS and HIFI) estimated the H2O mole fraction to be 0.023 ppb at 12.1 mbar. A mixing ratio of 0.14 ppb at 10.7 mbar was, however, retrieved from nadir spatially-resolved observations of Cassini/CIRS. At the same pressure level (10.7 mbar), this makes a difference of a factor of 5.5 between PACS and CIRS measurements, and this has notably prevented current models from fully constraining the oxygen flux flowing into Titan's atmosphere. In this work, we try to understand the differences between the H2O mole fractions estimated from Herschel/PACS and Cassini/CIRS observations. The strategy for this is to 1) analyse recent disc-averaged observations of CIRS to investigate if the observation geometry could explain the previous observed differences, and 2) (re)analyse the three types of observation with the same retrieval scheme to assess if previous differences in retrieval codes/methodology could be responsible for the previous discrepancies. With this analysis, we show that using the same retrieval method better reconcile the previous measurements of these instruments. However, the addition of the disc-averaged CIRS observations, instead of confirming the consistency between the different datasets, reveals discrepancies between one of the CIRS disc-averaged set of observations and PACS measurements. This raises new questions regarding the possibility of latitudinal variations of H2O, which could be triggered by seasonal changes of the meridional circulation. As it has already been shown for nitriles and hydrocarbons, this circulation could potentially impact the latitudinal distribution of H2O through the subsidence or upwelling of air rich in H2O. The possible influence of spatial/time variations of the OH/H2O input flux in Titan's atmosphere is also discussed. The analysis of more observations will be needed in future work to address the questions arising from this work and to improve the understanding of the sources of H2O in Titan's atmosphere. © 2018 Elsevier Inc.
BibTeX:
@article{BauduinIrwinLellouchEtAl2018,
  author = {Bauduin, S. and Irwin, P.G.J. and Lellouch, E. and Cottini, V. and Moreno, R. and Nixon, C.A. and Teanby, N.A. and Ansty, T. and Flasar, F.M.},
  title = {Retrieval of H2O abundance in Titan's stratosphere: A (re)analysis of CIRS/Cassini and PACS/Herschel observations},
  journal = {Icarus},
  year = {2018},
  volume = {311},
  pages = {288-305},
  doi = {10.1016/j.icarus.2018.04.003}
}
Abstract: The Lagrange-mesh method is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. With a basis of Lagrange functions involving associated Laguerre polynomials related to the Gauss quadrature, the method is applied to the Dirac equation. The potential may possess a 1/r singularity. For hydrogenic atoms, numerically exact energies and wave functions are obtained with small numbers n+1 of mesh points, where n is the principal quantum number. Numerically exact mean values of powers -2 to 3 of the radial coordinate r can also be obtained with n+2 mesh points. For the Yukawa potential, a 15-digit agreement with benchmark energies of the literature is obtained with 50 or fewer mesh points. © 2014 American Physical Society.
BibTeX:
@article{BayeFilippinGodefroid2014,
  author = {Baye, D. and Filippin, L. and Godefroid, M.},
  title = {Accurate solution of the Dirac equation on Lagrange meshes},
  journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics},
  year = {2014},
  volume = {89},
  article number = {043305},
  doi = {10.1103/PhysRevE.89.043305}
}
Abstract: We report on the projectile energy dependence of the cross sections for producing K Auger electrons in 2–170-keV [Formula Presented] collisions. The present studies, which extend previous work performed at the impact energy of 35 keV, give evidence for a dielectronic excitation process produced by electron-electron interaction. At impact energies in the range 5–170 keV, the cross sections are found to be larger than [Formula Presented] Molecular-orbital energy diagrams were determined to analyze details of the collision. Analytic models were used to evaluate cross sections associated with dielectronic excitation. The results show good agreement with experiment. The dielectronic excitation process is dominant when three electrons from the target are transferred into an excited state of the projectile. © 1999 The American Physical Society.
BibTeX:
@article{BedouetFremontChesnelEtAl1999,
  author = {Bedouet, C. and Frémont, F. and Chesnel, J.Y. and Husson, X. and Merabet, H. and Vaeck, N. and Zitane, N. and Sulik, B. and Grether, M. and Spieler, A. and Stolterfoht, N.},
  title = {Dielectronic excitation of Ne K-shell electrons in 2–170-keV [Formula Presented] collisions},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {1999},
  volume = {59},
  pages = {4399-4406},
  doi = {10.1103/PhysRevA.59.4399}
}
Abstract: Two recently developed methods for solving the molecular vibrational Schrödinger equation, namely, the parallel vibrational multiple window configuration interaction and the vibrational mean field configuration interaction, are presented and compared on the same potential energy surface of ethylene oxide, c-C2H4O. It is demonstrated on this heptatomic system with strong resonances that both approaches converge towards the same fundamental frequencies. This confirms their ability to tackle the vibrational problem of large molecules for which full configuration interaction calculations are not tractable. © 2007 American Institute of Physics.
BibTeX:
@article{BegueGohaudPouchanEtAl2007,
  author = {Bégué, D. and Gohaud, N. and Pouchan, C. and Cassam-Chenai, P. and Liévin, J.},
  title = {A comparison of two methods for selecting vibrational configuration interaction spaces on a heptatomic system: Ethylene oxide},
  journal = {Journal of Chemical Physics},
  year = {2007},
  volume = {127},
  article number = {164115},
  doi = {10.1063/1.2795711}
}
Abstract: After 43 years of inactivity, the Calbuco volcano, which is located in the southern part of Chile, erupted on 22 April 2015. The space-time evolutions (distribution and transport) of its aerosol plume are investigated by combining satellite (CALIOP, IASI, OMPS), in situ aerosol counting (LOAC OPC) and lidar observations, and the MIMOSA advection model. The Calbuco aerosol plume reached the Indian Ocean 1 week after the eruption. Over the Reunion Island site (21 S, 55.5 E), the aerosol signal was unambiguously enhanced in comparison with "background" conditions, with a volcanic aerosol layer extending from 18 to 21 km during the May-July period. All the data reveal an increase by a factor of 2 in the SAOD (stratospheric aerosol optical depth) with respect to values observed before the eruption. The aerosol mass e-folding time is approximately 90 days, which is rather close to the value (80 days) reported for the Sarychev eruption. Microphysical measurements obtained before, during, and after the eruption reflecting the impact of the Calbuco eruption on the lower stratospheric aerosol content have been analyzed over the Reunion Island site. During the passage of the plume, the volcanic aerosol was characterized by an effective radius of 0.160.02 μm with a unimodal size distribution for particles above 0.2 μm in diameter. Particle concentrations for sizes larger than 1 μm are too low to be properly detected by the LOAC OPC. The aerosol number concentration was 20 times higher that observed before and 1 year after the eruption. According to OMPS and lidar observations, a tendency toward conditions before the eruption was observed by April 2016. The volcanic aerosol plume is advected eastward in the Southern Hemisphere and its latitudinal extent is clearly bounded by the subtropical barrier and the polar vortex. The transient behavior of the aerosol layers observed above Reunion Island between May and July 2015 reflects an inhomogeneous spatio-temporal distribution of the plume, which is controlled by the localization of these dynamical barriers. © Author(s) 2017.
BibTeX:
@article{BegueVignellesBerthetEtAl2017,
  author = {Bègue, N. and Vignelles, D. and Berthet, G. and Portafaix, T. and Payen, G. and Jégou, F. and Benchérif, H. and Jumelet, J. and Lurton, T. and Renard, J.-B. and Clarisse, L. and Duverger, V. and Posny, F. and Metzger, J.-M. and Godin-Beekmann, S.},
  title = {Long-range transport of stratospheric aerosols in the Southern Hemisphere following the 2015 Calbuco eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {15019-15036},
  doi = {10.5194/acp-17-15019-2017}
}
Abstract: We report the application of the quantum approach, which takes full account of electron translation at low collisional energies, to the charge exchange process H, D + C4+ → H+, D+ + C 3+(3s; 3p; 3d). The partial and the total integral cross sections of the process are calculated in the energy range from 1 till 60 eV/amu. It is shown that the present results are independent from the upper integration limit for numerical solution of the coupled channel equations although nonadiabatic couplings remain nonzero up to infinity. The calculated partial and total cross sections are in agreement with the previous low-energy calculations and the available experimental data. It is shown that for low collisional energies the isotopic effect takes place. The observed effect is explained in terms of the nonadiabatic dynamics.
BibTeX:
@article{BelyaevGrosserLievinEtAl2002,
  author = {Belyaev, A.K. and Grosser, J. and Liévin, J. and Vaeck, N.},
  title = {Charge exchange in low-energy H, D + C4+ collisions with full account of electron translation},
  journal = {International Journal of Molecular Sciences},
  year = {2002},
  volume = {3},
  pages = {190-208},
  doi = {10.3390/i3030190}
}
BibTeX:
@article{BergerGelbckeCauetEtAl2015,
  author = {Berger, G. and Gelbcke, M. and Cauët, E. and Luhmer, M. and Nève, J. and Dufrasne, F.},
  title = {Erratum:Corrigendum to "synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds" (Tetrahedron Letters (2013) 54 (545-548) doi:10.1016/j.tetlet.2014.11.086))},
  journal = {Tetrahedron Letters},
  year = {2015},
  volume = {56},
  pages = {485},
  doi = {10.1016/j.tetlet.2014.11.086}
}
Abstract: A new method for the synthesis of 15N-labeled chiral β-diamines from a common precursor, either optically pure amino acids or anti-β-amino alcohols, is reported. The two diastereomeric series of vicinal diamines are produced through the nucleophilic ring opening of activated chiral aziridines. 15N was introduced by means of [ 15N]-benzylamine, prepared from 15NH4Cl. The final compounds are highly valuable because [1H-15N] NMR is considered a powerful tool for studying the chemical properties of platinum-based complexes. © 2012 Published by Elsevier Ltd.
BibTeX:
@article{BergerGelbckeCauetEtAl2013,
  author = {Berger, G. and Gelbcke, M. and Cauët, E. and Luhmer, M. and Nève, J. and Dufrasne, F.},
  title = {Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds},
  journal = {Tetrahedron Letters},
  year = {2013},
  volume = {54},
  pages = {545-548},
  doi = {10.1016/j.tetlet.2012.11.079}
}
Abstract: The Wulf bands of oxygen in the 240-290 nm spectral region are caused by collision-induced absorption of the Herzberg III (A′3Δu-X3Σ- g) system. These bands had been previously attributed to the oxygen dimer, (O2)2. Under atmospheric conditions the Wulf bands are thus the long-wavelength extension of the Herzberg continuum. Absorption of solar radiation by the Wulf bands may be an additional source of NO in the stratosphere. © 1998 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{BernathCarleerFallyEtAl1998,
  author = {Bernath, P. and Carleer, M. and Fally, S. and Jenouvrier, A. and Vandaele, A.C. and Hermans, C. and Mérienne, M.-F. and Colin, R.},
  title = {The Wulf bands of oxygen},
  journal = {Chemical Physics Letters},
  year = {1998},
  volume = {297},
  pages = {293-299},
  doi = {10.1016/S0009-2614(98)01149-X}
}
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-13) and B2Σ+ (v = 0 and 1) states of the OH radical. They are derived from a fit of previously published laboratory data and additional lines taken from infrared solar spectra recorded on orbit. © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{BernathColin2009,
  author = {Bernath, P.F. and Colin, R.},
  title = {Revised molecular constants and term values for the X2Π and B2Σ+ states of OH},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {257},
  pages = {20-23},
  doi = {10.1016/j.jms.2009.06.003}
}
Abstract: SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{BernathMcElroyAbramsEtAl2005,
  author = {Bernath, P.F. and McElroy, C.T. and Abrams, M.C. and Boone, C.D. and Butler, M. and Camy-Peyret, C. and Carleer, M. and Clerbaux, C. and Coheur, P.-F. and Colin, R. and DeCola, P. and DeMazière, M. and Drummond, J.R. and Dufour, D. and Evans, W.F.J. and Fast, H. and Fussen, D. and Gilbert, K. and Jennings, D.E. and Llewellyn, E.J. and Lowe, R.P. and Mahieu, E. and McConnell, J.C. and McHugh, M. and McLeod, S.D. and Michaud, R. and Midwinter, C. and Nassar, R. and Nichitiu, F. and Nowlan, C. and Rinsland, C.P. and Rochon, Y.J. and Rowlands, N. and Semeniuk, K. and Simon, P. and Skelton, R. and Sloan, J.J. and Soucy, M.-A. and Strong, K. and Tremblay, P. and Turnbull, D. and Walker, K.A. and Walkty, I. and Wardle, D.A. and Wehrle, V. and Zander, R. and Zou, J.},
  title = {Atmospheric chemistry experiment (ACE): Mission overview},
  journal = {Geophysical Research Letters},
  year = {2005},
  volume = {32},
  article number = {L15S01},
  doi = {10.1029/2005GL022386}
}
Abstract: The gaseous BeH2 molecule has been synthesized by means of an electrical discharge inside a high-temperature furnace and identified with infrared emission spectroscopy. The antisymmetric stretching mode v3 has been detected near 2179 reciprocal centimeters. The BeH2 molecule has a linear, symmetric structure with an ro BeH bond length of 1.333761(2) angstroms.
BibTeX:
@article{BernathShayestehTereszchukEtAl2002,
  author = {Bernath, P.F. and Shayesteh, A. and Tereszchuk, K. and Colin, R.},
  title = {The vibration-rotation emission spectrum of free BeH2},
  journal = {Science},
  year = {2002},
  volume = {297},
  pages = {1323-1324},
  doi = {10.1126/science.1074580}
}
Abstract: In this study, experimental and theoretical values for the oscillator strengths of the 5s2 1S0-5s5p 1,3P10 transitions and for the lifetimes of the 5s5p 1,3P10 levels in the Cd isoelectronic sequence were examined in the context of the evaluation of the importance of core-polarization effects. Erroneous or inaccurate measurements were identified using regularities along the sequence and coherence among the HFR and MCDF results.
BibTeX:
@article{BiemontFischerGodefroidEtAl2000,
  author = {Biémont, E. and Fischer, C.F. and Godefroid, M.R. and Palmeri, P. and Quinet, P.},
  title = {Core-polarization effects in the cadmium isoelectronic sequence},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2000},
  volume = {62},
  pages = {032512-032511}
}
Abstract: The oscillator strengths of the allowed and spin-forbidden [Formula Presented] transitions in the cadmium isoelectronic sequence are evaluated for [Formula Presented] using the relativistic Hartree-Fock approach, including a core-polarization potential, and the multiconfiguration Dirac-Fock method, taking the valence and core-valence correlation effects into account. A good agreement is noted when comparing the two sets of theoretical data and when comparing theory with experiment for the spin-forbidden transition. The discrepancies observed between theory (both theories being in agreement) and experiment for the singlet-singlet transition indicate that some experimental data are in need of revision. © 2000 The American Physical Society.
BibTeX:
@article{BiemontFischerGodefroidEtAl2000a,
  author = {Biémont, E. and Fischer, C.F. and Godefroid, M.R. and Palmeri, P. and Quinet, P.},
  title = {Core-polarization effects in the cadmium isoelectronic sequence},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2000},
  volume = {62},
  pages = {8},
  doi = {10.1103/PhysRevA.62.032512}
}
Abstract: Nonrelativistic multiconfiguration Hartree–Fock wavefunctions and oscillator strengths are reported for selected transitions of neutral zinc and of its isoelectronic sequence up to W XLV. Correlation among the outer electrons has been considered in a detailed way. The final values, when compared with the few experimental observations or theoretical calculations available at the neutral end of the sequence, agree well with the most recent and accurate results published for Zn I. © 1980 IOP Publishing Ltd.
BibTeX:
@article{BiemontGodefroid1980,
  author = {Biemont, E. and Godefroid, M.},
  title = {Outer correlation MCHF wavefunctions and oscillator strengths along the zinc isoelectronic sequence},
  journal = {Physica Scripta},
  year = {1980},
  volume = {22},
  pages = {231-239},
  doi = {10.1088/0031-8949/22/3/009}
}
Abstract: In an attempt to refine our knowledge of the solar abundances of the CNO elements, we discuss in this paper the implications of a new accurate set of oscillator strengths recently calculated in intermediate coupling for the 2p(2Po)nl-2p(2Po)n′l′ E1 transitions of astrophysical interest in C I and also for the forbidden transitions within the 2p2 ground configuration. As with previous analyses devoted to nitrogen and oxygen, configuration interaction effects have been considered in the calculations in a detailed way and empirical adjustments have been introduced in the diagonal Hamiltonian matrix elements in order to improve the agreement between theoretical eigenvalues and experimental energy differences. The new LTE result, based on a sample of 55 E1 transitions observed in the visible and in the near infrared regions, is AC = 8.60 ± 0.03 in the usual logarithmic scale. Taking departures from LTE into account leads, for a sample of 31 weak lines, to a mean result AC = 8.57 ± 0.03 in agreement with recent determinations.
BibTeX:
@article{BiemontHibbertGodefroidEtAl1993,
  author = {Biémont, E. and Hibbert, A. and Godefroid, M. and Vaeck, N.},
  title = {New f-values in C I and the CNO abundances in the sun},
  journal = {Astrophysical Journal},
  year = {1993},
  volume = {412},
  pages = {431-435},
  doi = {10.1086/172932}
}
Abstract: Knowledge of accurate oscillator strengths in neutral oxygen is of crucial importance in astrophysics. The accurate determination of the solar abundance of O I, which remains the primary source for the entry in cosmic abundance tables, requires the use of E1 transitions appearing in the solar photospheric spectrum. A new accurate scale of oscillator strengths has therefore been obtained for the 2p3(4S)nl-2p3(4S)n′l′ transitions of O I of astrophysical interest. Configuration interaction effects have been considered in a detailed way. The results have been used to improve the solar abundance determination for oxygen. The new result is A(O) = 8.86 ± 0.04 (in the usual logarithmic scale).
BibTeX:
@article{BiemontHibbertGodefroidEtAl1991,
  author = {Biémont, E. and Hibbert, A. and Godefroid, M. and Vaeck, N. and Fawcett, B.C.},
  title = {Accurate oscillator strengths of astrophysical interest for neutral oxygen},
  journal = {Astrophysical Journal},
  year = {1991},
  volume = {375},
  pages = {818-822},
  doi = {10.1086/170245}
}
Abstract: The relativistic multiconfiguration Dirac-Hartree-Fock and the nonrelativistic multiconfiguration Hartree-Fock methods have been employed to calculate the magnetic dipole and electric quadrupole hyperfine structure constants of zinc. The calculated electric field gradients for the 4s4pP1o3 and 4s4pP2o3 states, together with experimental values of the electric quadrupole hyperfine structure constants, made it possible to extract a nuclear electric quadrupole moment Q(Zn67)=0.122(10) b. The error bar was evaluated in a quasistatistical approach - the calculations were carried out with 11 different methods, and then the error bar was estimated from the differences between the results obtained with those methods. © 2018 American Physical Society.
BibTeX:
@article{BieronFilippinGaigalasEtAl2018,
  author = {Bieroń, J. and Filippin, L. and Gaigalas, G. and Godefroid, M. and Jönsson, P. and Pyykkö, P.},
  title = {Ab initio calculations of the hyperfine structure of zinc and evaluation of the nuclear quadrupole moment Q(Zn 67)},
  journal = {Physical Review A},
  year = {2018},
  volume = {97},
  article number = {062505},
  doi = {10.1103/PhysRevA.97.062505}
}
Abstract: The multi-configuration Dirac-Fock model is used to evaluate the magnetic dipole hyperfine interaction constants of the 3d4s(1D)4p 2D3/2,5/20, 3d4s(3D)4p 4F9/20, 3d4s(1D)4p 2F5/2,7/20 and 3d2(1D)4s 2D3/2,5/2 levels of atomic scandium. The wavefunctions are obtained with the active space expansion method, where configuration state functions of a specific parity and J value are generated by substitutions from the reference configurations to an active set of orbitals. The active set is then increased in a systematic way, allowing the convergence of the expectation values to be monitored. The calculated magnetic dipole hyperfine interaction constants are compared with experimentally determined values. On the grounds of the level of agreement between experiment and theory, we confirm three of the hypothetical A-values, previously deduced from high-resolution Fourier transform spectroscopy.
BibTeX:
@article{BieronFischerGodefroid2002,
  author = {Bieron, J. and Fischer, C.F. and Godefroid, M.},
  title = {Hyperfine-structure calculations of excited levels in neutral scandium},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2002},
  volume = {35},
  pages = {3337-3345},
  doi = {10.1088/0953-4075/35/15/308}
}
Abstract: Collinear laser spectroscopy on Cu58-75 isotopes was performed at the CERN-ISOLDE radioactive ion beam facility. In this paper we report on the isotope shifts obtained from these measurements. State-of-the-art atomic physics calculations have been undertaken in order to determine the changes in mean-square charge radii δ(r2)A,A′ from the observed isotope shifts. A local minimum is observed in these radii differences at N=40, providing evidence for a weak N=40 sub-shell effect. However, comparison of δ(r2)A,A′ with a droplet model prediction including static deformation deduced from the spectroscopic quadrupole moments, points to the persistence of correlations at N=40. © 2016 authors. Published by the American Physical Society.
BibTeX:
@article{BissellCaretteFlanaganEtAl2016,
  author = {Bissell, M.L. and Carette, T. and Flanagan, K.T. and Vingerhoets, P. and Billowes, J. and Blaum, K. and Cheal, B. and Fritzsche, S. and Godefroid, M. and Kowalska, M. and Krämer, J. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Yordanov, D.T.},
  title = {Cu charge radii reveal a weak sub-shell effect at N=40},
  journal = {Physical Review C},
  year = {2016},
  volume = {93},
  article number = {064318},
  doi = {10.1103/PhysRevC.93.064318}
}
Abstract: A study was performed on the (3 + 1)-resonantly enhanced multiphoton ionization-photoelectron spectroscopy of the (3d-4s) supercomplex of acetylene. The Renner-Teller coupling occurring in the ion ground state was considered during the photoelectron analysis. The results showed the tentative frequencies for the stretching mode as well as for the bending mode.
BibTeX:
@article{BlanchetBoyeZamithEtAl2003,
  author = {Blanchet, V. and Boyé, S. and Zamith, S. and Campos, A. and Girard, B. and Liévin, J. and Gauyacq, D.},
  title = {(3+1)-resonantly enhanced multiphoton ionization-photoelectron spectroscopy of the (3d-4s) supercomplex of acetylene: The geometry of the E state revisited through experiment and theory},
  journal = {Journal of Chemical Physics},
  year = {2003},
  volume = {119},
  pages = {3751-3762},
  doi = {10.1063/1.1589480}
}
Abstract: The N2-broadening coefficients of ethane for 15 lines in the ν9 band at five pressures of nitrogen were measured. The measurements were carried out with a 1-m base White-type cell adjusted for four transits, yielding an optical path of 4.17 m. The average values of the N2-broadening coefficients obtained at 296 K from the Voigt and Rautian line shapes are respectively equal to 0.0822 and 0.0864 cm-1 atm-1. The results derived from the Voigt profile are 2 10% lower than those derived from the Rautian model. No rotational dependence is observed over the limited range of rotational quantum numbers investigated. The results also show that the adjustment of the Rautian profile provides an additional parameter, the collisional narrowing coefficient β0.
BibTeX:
@article{BlanquetAuweraLepere2009,
  author = {Blanquet, G. and Auwera, J.V. and Lepère, M.},
  title = {N2-broadening coefficients of ethane},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {255},
  pages = {72-74},
  doi = {10.1016/j.jms.2009.02.020}
}
Abstract: Photodetachment microscopy has been used in a double-pass, field-collinear scheme in order to measure the electron affinity of atomic oxygen. As an illustration of the sensitivity of the method, electron images could be recorded even from the rarest [Formula Presented] ion. Analysis of photodetachment images recorded with this odd isotope, however, requires that one knows the unresolved hyperfine structures of the ground states of both the neutral atom [Formula Presented] and the negative ion. Calculation of the hyperfine structure of [Formula Presented] was achieved, which permitted to add the electron affinity of [Formula Presented] to the series of the measured electron affinities of oxygen isotopes. The anomalous isotope shift of these electron affinities is finally compared with ab initio calculations. © 2001 The American Physical Society.
BibTeX:
@article{BlondelDelsartValliEtAl2001,
  author = {Blondel, C. and Delsart, C. and Valli, C. and Yiou, S. and Godefroid, M.R. and Van Eck, S.},
  title = {Electron affinities of [Formula Presented] [Formula Presented] [Formula Presented] the fine structure of [Formula Presented] and the hyperfine structure of [Formula Presented]},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2001},
  volume = {64},
  pages = {14},
  doi = {10.1103/PhysRevA.64.052504}
}
Abstract: Measurement of electron affinity of atomic oxygen was done using a photodetachment microscopy. For 17O-, calculation of the hyperfine structure was done, which permitted to add the electron affinity of 17O to the series of the measured electron affinities of oxygen isotopes. Comparison of the anomalous isotope shift of these electron affinities was done with ab initio calculations.
BibTeX:
@article{BlondelDelsartValliEtAl2001a,
  author = {Blondel, C. and Delsart, C. and Valli, C. and Yiou, S. and Godefroid, M.R. and Van Eck, S.},
  title = {Electron affinities of 16O, 17O, 18O, the fine structure of 16O-, and the hyperfine structure of 17O-},
  journal = {Physical Review A. Atomic, Molecular, and Optical Physics},
  year = {2001},
  volume = {64},
  article number = {052504},
  pages = {525041-5250414}
}
Abstract: Herein, we report on the structure and dynamics of the aqueous Ca 2+ system studied by using ab initio molecular dynamics (AIMD) simulations. Our detailed study revealed the formation of well-formed hydration shells with characteristics that were significantly different to those of bulk water. To facilitate a robust comparison with state-of-the-art X-ray absorption fine structure (XAFS) data, we employ a 1st principles MD-XAFS procedure and directly compare simulated and experimental XAFS spectra. A comparison of the data for the aqueous Ca2+ system with those of the recently reported Zn2+, Fe3+, and Al3+ species showed that many of their structural characteristics correlated well with charge density on the cation. Some very important exceptions were found, which indicated a strong sensitivity of the solvent structure towards the cation′s valence electronic structure. Average dipole moments for the 2nd shell of all cations were suppressed relative to bulk water. Like a duck to water: An investigation into the solvent structure and dynamics around the Ca2+ cation was validated by comparison with XAFS data. A comparison with ab initio molecular dynamics studies of aqueous Zn2+, Fe3+, and Al 3+ was used to discuss general trends in the ability of these solvated cations to form extended structures. Copyright © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.
BibTeX:
@article{BogatkoCauetBylaskaEtAl2013,
  author = {Bogatko, S. and Cauët, E. and Bylaska, E. and Schenter, G. and Fulton, J. and Weare, J.},
  title = {The aqueous Ca2+ system, in comparison with Zn2+, Fe3 +, and Al3 +: An ab initio molecular dynamics study},
  journal = {Chemistry - A European Journal},
  year = {2013},
  volume = {19},
  pages = {3047-3060},
  doi = {10.1002/chem.201202821}
}
Abstract: We present results showing that our recently developed density functional theory (DFT)-based speciation model of the aqueous Al3+ system has the potential to improve the interpretations of ESI-MS studies of aqueous metal cation hydrolytic speciation. The main advantages of our method are that (1) it allows for the calculation of the relative abundance of a given species which may be directly assigned to the signal intensity in a mass spectrum; (2) in cases where species with identical m/z ratios may coexist, the assignment can be unambiguously assigned based on their theoretical relative abundances. As a demonstration of its application, we study four pairs of monomer and dimer aqueous Al3+ species, each with identical m/z ratio. For some of these pairs our method predicts that the dominant species changes from the monomer to the dimer species under varying pH conditions. [Figure not available: see fulltext.] © 2013 American Society for Mass Spectrometry.
BibTeX:
@article{BogatkoCauetGeerlings2013,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Improved DFT-based interpretation of ESI-MS of aqueous metal cations},
  journal = {Journal of the American Society for Mass Spectrometry},
  year = {2013},
  volume = {24},
  pages = {926-931},
  doi = {10.1007/s13361-013-0617-x}
}
Abstract: We predict that electron attachment may be used with ESI-MS techniques to observe neutral Al metal aqua-oxo-hydroxo species and the complex polymerization and precipitation reactions in which they participate. Neutral aqueous metal species have, so far, been invisible to ESI-MS techniques. This journal is © 2013 the Owner Societies.
BibTeX:
@article{BogatkoCauetGeerlings2013a,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Rydberg electron capture by neutral Al hydrolysis products},
  journal = {Physical Chemistry Chemical Physics},
  year = {2013},
  volume = {15},
  pages = {15309-15311},
  doi = {10.1039/c3cp51935j}
}
Abstract: Aqua/hydroxo mononuclear Al3+ species coordinated by F - in aqueous solution are investigated using density functional theory (DFT B3LYP/6-311++G(d,p)) and the polarized continuum model (PCM). Optimized gas-phase geometries have been obtained for the species AlF(OH) n(H2O)m(2-n)+ in which n = 0, 1, 2, or 3 while (n + m) = 3, 4, or 5. Analysis of the Al-F, Al-O, and O-H bond lengths and the Al, F, O, and H natural charges of these complexes reveals clear trends that suggest increased acidity with decreasing coordination number (CN) and decreased water stability with increased hydrolysis. These observations are supported by the calculation and analysis of the dehydration and hydrolysis reaction Gibbs free energies δGaqueous dehydration and δGaqueous hydrolysis of the AlF(OH)n(H2O)m(2-n) + complexes, which clearly show a strong correlation between increased hydrolysis and a preference to coordinate fewer water molecules. The combination of the appropriate δGaqueous dehydration and δGaqueous hydrolysis values generate the aqueous Gibbs free energies relative to AlF(H2O)52+ and demonstrate the clear transition from a 6 to 5 to 4 coordinate species as a function of ligand hydrolysis. Calculation of the equilibrium mole fraction of each species as a function of pH shows that this system is largely dominated by the AlF(OH) 1(H2O)41+ and AlF(OH) 31- species. A comparison of structural and electronic data with the aqueous Al3+ complexes shows a remarkable similarity when plotted against the number negative ligands (F- or OH -), suggesting that the F- anion coordinates the Al 3+ cation in a similar way to the remaining OH- anions. The comparison of the calculated equilibrium mole fractions of each species displays important changes in the composition of our model system upon Al 3+ coordination by F- in the direction of increased acidity of these complexes. Our predicted decreased stability of the Al-water bond is in complete agreement with experimental NMR observations of an increased water exchange rate upon F- coordination of aqueous aluminum complexes. Our prediction of stable hydroxide ternary complexes is not in agreement with recent NMR data, which indicate that these complexes do not readily form. An explanation for this may lie in the increased lability of these complexes, which may lead to difficulties in NMR detection. © 2011 American Chemical Society.
BibTeX:
@article{BogatkoCauetGeerlings2011,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P.},
  title = {Influence of F- coordination on Al3+ hydrolysis reactions from density functional theory calculations},
  journal = {Journal of Physical Chemistry C},
  year = {2011},
  volume = {115},
  pages = {6910-6921},
  doi = {10.1021/jp112076r}
}
Abstract: We present the results of a theoretical investigation focusing on the solvent structure surrounding the -1, 0 and +1 charged species of F, Cl, Br and I halogen atoms and F2, Cl2, Br2 and I 2 di-halogen molecules in a methanol solvent and its influence on the electronic structure of the solute molecules. Our results show a large stabilizing effect arising from the solute-solvent interactions. Well-formed first solvation shells are observed for all species, the structure of which is strongly influenced by the charge of the solute species. Detailed analysis reveals that coordination number, CN, solvent orientation, and solute-solvent distance, d, are important structural characteristics which are coupled to changes in the electronic structure of the solute. We propose that the fundamental chemistry of any solute species is generally regulated by these solvent degrees of freedom. © 2014 the Owner Societies.
BibTeX:
@article{BogatkoCauetGeerlingsEtAl2014,
  author = {Bogatko, S. and Cauët, E. and Geerlings, P. and De Proft, F.},
  title = {On the coupling of solvent characteristics to the electronic structure of solute molecules},
  journal = {Physical Chemistry Chemical Physics},
  year = {2014},
  volume = {16},
  pages = {3807-3814},
  doi = {10.1039/c3cp54944e}
}
Abstract: The 2014-2015 Holuhraun lava-flood eruption of Bároarbunga volcano (Iceland) emitted prodigious amounts of sulfur dioxide into the atmosphere. This eruption caused a large-scale episode of air pollution throughout Western Europe in September 2014, the first event of this magnitude recorded in the modern era. We gathered chemistry-transport simulations and a wealth of complementary observations from satellite sensors (OMI, IASI), ground-based remote sensing (lidar, sunphotometry, differential optical absorption spectroscopy) and ground-level air quality monitoring networks to characterize both the spatial-temporal distributions of volcanic SO2 and sulfate aerosols as well as the dynamics of the planetary boundary layer. Time variations of dynamical and microphysical properties of sulfate aerosols in the aged low-tropospheric volcanic cloud, including loading, vertical distribution, size distribution and single scattering albedo, are provided. Retrospective chemistry-transport simulations at low horizontal resolution (25 km × 25 km) capture the correct temporal dynamics of this far-range air pollution event but fail to reproduce the correct magnitude of SO2 concentration at ground-level. Simulations at higher spatial resolution, relying on two nested domains with finest resolution of 7.3 km × 7.3 km, improve substantially the far-range vertical distribution of the volcanic cloud and subsequently the description of ground-level SO2 concentrations. However, remaining discrepancies between model and observations are shown to result from an inaccurate representation of the planetary boundary layer (PBL) dynamics. Comparison with lidar observations points out a systematic under-estimation of the PBL height by the model, whichever the PBL parameterization scheme. Such a shortcoming impedes the capture of the overlying Bároarbunga cloud into the PBL at the right time and in sufficient quantities. This study therefore demonstrates the key role played by the PBL dynamics in accurately modelling large-scale volcanogenic air pollution. © 2016 Author(s).
BibTeX:
@article{BoichuChiapelloBrogniezEtAl2016,
  author = {Boichu, M. and Chiapello, I. and Brogniez, C. and Péré, J.-C. and Thieuleux, F. and Torres, B. and Blarel, L. and Mortier, A. and Podvin, T. and Goloub, P. and Söhne, N. and Clarisse, L. and Bauduin, S. and Hendrick, F. and Theys, N. and Van Roozendael, M. and Tanré, D.},
  title = {Current challenges in modelling far-range air pollution induced by the 2014-2015 Bároarbunga fissure eruption (Iceland)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10831-10845},
  doi = {10.5194/acp-16-10831-2016}
}
Abstract: Forecasting the dispersal of volcanic clouds during an eruption is of primary importance, especially for ensuring aviation safety. As volcanic emissions are characterized by rapid variations of emission rate and height, the (generally) high level of uncertainty in the emission parameters represents a critical issue that limits the robustness of volcanic cloud dispersal forecasts. An inverse modeling scheme, combining satellite observations of the volcanic cloud with a regional chemistry-transport model, allows reconstructing this source term at high temporal resolution. We demonstrate here how a progressive assimilation of freshly acquired satellite observations, via such an inverse modeling procedure, allows for delivering robust sulfur dioxide (SO2) cloud dispersal forecasts during the eruption. This approach provides a computationally cheap estimate of the expected location and mass loading of volcanic clouds, including the identification of SO2-rich parts. Key Points Refined SO2 cloud dispersal forecasts by assimilation of satellite observations Refined estimation of source emissions using an inverse modeling approach Compared to standard methods, cloud SO2-rich parts are robustly forecasted © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BoichuClarisseKhvorostyanovEtAl2014,
  author = {Boichu, M. and Clarisse, L. and Khvorostyanov, D. and Clerbaux, C.},
  title = {Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {2637-2643},
  doi = {10.1002/2014GL059496}
}
Abstract: Sulfur-rich degassing, which is mostly composed of sulfur dioxide (SO2), plays a major role in the overall impact of volcanism on the atmosphere and climate. The accurate assessment of this impact is currently hampered by the poor knowledge of volcanic SO2 emissions. Here, using an inversion procedure, we show how assimilating snapshots of the volcanic SO2 load derived from the Infrared Atmospheric Sounding Interferometer (IASI) allows for reconstructing both the flux and altitude of the SO2 emissions with an hourly resolution. For this purpose, the regional chemistry-transport model CHIMERE is used to describe the dispersion of SO2 when released in the atmosphere. As proof of concept, we study the 10 April 2011 eruption of the Etna volcano (Italy), which represents one of the few volcanoes instrumented on the ground for the continuous monitoring of SO2 degassing. We find that the SO2 flux time-series retrieved from satellite imagery using the inverse scheme is in agreement with ground observations during ash-poor phases of the eruption. However, large discrepancies are observed during the ash-rich paroxysmal phase as a result of enhanced plume opacity affecting ground-based ultraviolet (UV) spectroscopic retrievals. As a consequence, the SO2 emission rate derived from the ground is underestimated by almost one order of magnitude. Altitudes of the SO2 emissions predicted by the inverse scheme are validated against an RGB image of the Moderate Resolution Imaging Spectroradiometer (MODIS) capturing the near-source atmospheric pathways followed by Etna plumes, in combination with forward trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. At a large distance from the source, modelled SO2 altitudes are compared with independent information on the volcanic cloud height. We find that the altitude predicted by the inverse scheme is in agreement with snapshots of the SO2 height retrieved from recent algorithms exploiting the high spectral resolution of IASI. The validity of the modelled SO2 altitude is further confirmed by the detection of a layer of particles at the same altitude by the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Analysis of CALIOP colour and depolarization ratios suggests that these particles consist of sulfate aerosols formed from precursory volcanic SO2. The reconstruction of emission altitude, through inversion procedures which assimilate volcanic SO2 column amounts, requires specific meteorological conditions, especially sufficient wind shear so that gas parcels emitted at different altitudes follow distinct trajectories. We consequently explore the possibility and limits of assimilating in inverse schemes infrared (IR) imagery of the volcanic SO2 cloud altitude which will render the inversion procedure independent of the wind shear prerequisite. © Author(s) 2015.
BibTeX:
@article{BoichuClarissePereEtAl2015,
  author = {Boichu, M. and Clarisse, L. and Péré, J.-C. and Herbin, H. and Goloub, P. and Thieuleux, F. and Ducos, F. and Clerbaux, C. and Tanré, D.},
  title = {Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: Implications for long-range dispersal of volcanic clouds},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8381-8400},
  doi = {10.5194/acp-15-8381-2015}
}
Abstract: Depending on the magnitude of their eruptions, volcanoes impact the atmosphere at various temporal and spatial scales. The volcanic source remains a major unknown to rigorously assess these impacts. At the scale of an eruption, the limited knowledge of source parameters, including time variations of erupted mass flux and emission profile, currently represents the greatest issue that limits the reliability of volcanic cloud forecasts. Today, a growing number of satellite and remote sensing observations of distant plumes are becoming available, bringing indirect information on these source terms. Here, we develop an inverse modelling approach combining satellite observations of the volcanic plume with an Eulerian regional chemistry-transport model (CHIMERE) to characterise the volcanic SO2 emissions during an eruptive crisis. The May 2010 eruption of Eyjafjallajökull is a perfect case study to apply this method as the volcano emitted substantial amounts of SO2 during more than a month. We take advantage of the SO2 column amounts provided by a vast set of IASI (Infrared Atmospheric Sounding Interferometer) satellite images to reconstruct retrospectively the time series of the mid-tropospheric SO2 flux emitted by the volcano with a temporal resolution of ∼2 h, spanning the period from 1 to 12 May 2010. We show that no a priori knowledge on the SO2 flux is required for this reconstruction. The initialisation of chemistry-transport modelling with this reconstructed source allows for reliable simulation of the evolution of the long-lived tropospheric SO2 cloud over thousands of kilometres. Heterogeneities within the plume, which mainly result from the temporal variability of the emissions, are correctly tracked over a timescale of a week. The robustness of our approach is also demonstrated by the broad similarities between the SO2 flux history determined by this study and the ash discharge behaviour estimated by other means during the phases of high explosive activity at Eyjafjallajö kull in May 2010. Finally, we show how a sequential IASI data assimilation allows for a substantial improvement in the forecasts of the location and concentration of the plume compared to an approach assuming constant flux at the source. As the SO2 flux is an important indicator of the volcanic activity, this approach is also of interest to monitor poorly instrumented volcanoes from space. © Author(s) 2013.
BibTeX:
@article{BoichuMenutKhvorostyanovEtAl2013,
  author = {Boichu, M. and Menut, L. and Khvorostyanov, D. and Clarisse, L. and Clerbaux, C. and Turquety, S.},
  title = {Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {8569-8584},
  doi = {10.5194/acp-13-8569-2013}
}
Abstract: During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ~100‰δD enrichment and ~15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BonneSteen-LarsenRisiEtAl2015,
  author = {Bonne, J.-L. and Steen-Larsen, H.C. and Risi, C. and Werner, M. and Sodemann, H. and Lacour, J.-L. and Fettweis, X. and Cesana, G. and Delmotte, M. and Cattani, O. and Vallelonga, P. and Kjær, H.A. and Clerbaux, C. and Sveinbjörnsdóttir, Á.E. and Masson-Delmotte, V.},
  title = {The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event},
  journal = {Journal of Geophysical Research},
  year = {2015},
  volume = {120},
  pages = {2970-2989},
  doi = {10.1002/2014JD022602}
}
Abstract: F- negative ions were detected by direct observation of the weak photodetachment absorption continuum below 364.5 nm by cavity ring-down spectroscopy. The negative ions were generated in a modified industrial dielectric plasma etch reactor, with 2+27 MHz dual frequency capacitive excitation in ArC F4 O2 and Ar C4 F8 O2 gas mixtures. The F- signal was superimposed on an unidentified absorption continuum, which was diminished by O2 addition. The F- densities were in the range of (0.5-3) × 1011 cm-3, and were not significantly different for single (27 MHz) or dual (2+27 MHz) frequency excitation, not confirming recent modeling predictions. © 2006 American Institute of Physics.
BibTeX:
@article{BoothCorrCurleyEtAl2006,
  author = {Booth, J.-P. and Corr, C.S. and Curley, G.A. and Jolly, J. and Guillon, J. and Földes, T.},
  title = {Fluorine negative ion density measurement in a dual frequency capacitive plasma etch reactor by cavity ring-down spectroscopy},
  journal = {Applied Physics Letters},
  year = {2006},
  volume = {88},
  article number = {151502},
  doi = {10.1063/1.2194823}
}
Abstract: A novel quantum similarity measure (QSM) is constructed based on concepts from information theory. In an application of QSM to atoms, the new QSM and its corresponding quantum similarity index (QSI) are evaluated throughout the periodic table, using the atomic electron densities and shape functions calculated in the Hartree-Fock approximation. The periodicity of Mendeleev's table is regained for the first time through the evaluation of a QSM. Evaluation of the information theory based QSI demonstrates, however, that the patterns of periodicity are lost due to the renormalization of the QSM, yielding chemically less appealing results for the QSI. A comparison of the information content of a given atom on top of a group with the information content of the elements in the subsequent rows reveals another periodicity pattern. Relativistic effects on the electronic density functions of atoms are investigated. Their importance is quantified in a QSI study by comparing for each atom, the density functions evaluated in the Hartree-Fock and Dirac-Fock approximations. The smooth decreasing of the relevant QSI along the periodic table illustrates in a quantitative way the increase of relativistic corrections with the nuclear charge. © 2007 American Institute of Physics.
BibTeX:
@article{BorgooGodefroidIndelicatoEtAl2007,
  author = {Borgoo, A. and Godefroid, M. and Indelicato, P. and De Proft, F. and Geerlings, P.},
  title = {Quantum similarity study of atomic density functions: Insights from information theory and the role of relativistic effects},
  journal = {Journal of Chemical Physics},
  year = {2007},
  volume = {126},
  article number = {044102},
  doi = {10.1063/1.2428295}
}
Abstract: In this Letter Quantum Similarity for Atoms (H-Xe) is investigated using electron densities and shape functions, looking for patterns of periodicity as in Mendeleev's Table. An LS-dependent restricted Hartree-Fock method is used to obtain the wave functions from which the electron densities are calculated. Utilizing the quantum similarity proposed by Carbó a nearest neighbour dominated similarity is retrieved, masking periodicity. Introduction of the information discrimination concept with reference to the noble gas atom of the previous row is found to reveal periodicity, with improved results when densities are replaced by shape functions throughout. This confirms recent literature on the fundamental role of the shape function as carrier of information. © 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{BorgooGodefroidSenEtAl2004,
  author = {Borgoo, A. and Godefroid, M. and Sen, K.D. and De Proft, F. and Geerlings, P.},
  title = {Quantum similarity of atoms: A numerical Hartree-Fock and Information Theory approach},
  journal = {Chemical Physics Letters},
  year = {2004},
  volume = {399},
  pages = {363-367},
  doi = {10.1016/j.cplett.2004.10.026}
}
Abstract: A new atsp2K module is presented for evaluating the electron density function of any multiconfiguration Hartree-Fock or configuration interaction wave function in the non-relativistic or relativistic Breit-Pauli approximation. It is first stressed that the density function is not a priori spherically symmetric in the general open shell case. Ways of building it as a spherical symmetric function are discussed, from which the radial electron density function emerges. This function is written in second quantized coupled tensorial form for exploring the atomic spherical symmetry. The calculation of its expectation value is performed using the angular momentum theory in orbital, spin, and quasispin spaces, adopting a generalized graphical technique. The natural orbitals are evaluated from the diagonalization of the density matrix. Program summary: Program title: DENSITY. Catalogue identifier: AEFR_v1_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFR_v1_0.html. Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html. No. of lines in distributed program, including test data, etc.: 6603. No. of bytes in distributed program, including test data, etc.: 169 881. Distribution format: tar.gz. Programming language: FORTRAN 90. Computer: HP XC Cluster Platform 4000. Operating system: HP XC System Software 3.2.1, which is a Linux distribution compatible with Red Hat Enterprise Advanced Server. Word size: 32 bits. Classification: 2.1, 2.9, 4.1. Subprograms used:A table is presented. Nature of problem: This program determines the atomic electronic density in the MCHF (LS) or Breit-Pauli (LS J) approximation. It also evaluates the natural orbitals by diagonalizing the density matrix. Solution method: Building the density operator using second quantization - spherical symmetry averaging - evaluating the matrix elements of the one-body excitation operators in the configuration state function (CSF) space using the angular momentum theory in orbital, spin, and quasispin spaces. Restrictions: Original restrictions from ATSP2K package, i.e. all orbitals within a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight subshells in addition to the closed shells common to all configuration states. The maximum size of the working arrays, related to the number of CSFs and active orbitals, is limited by the available memory and disk space. Unusual features: The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade, but their implementations are compiler dependent. The present code has been installed and tested extensively using the Portland Group, pgf90, compiler. Running time: The calculation of the electron density for an n = 9 complete active space (CAS) MCHF wave function (271 733 CSFs - 45 orbitals) takes around 9 minutes on one AMD Opteron dual-core at 2.4 GHz CPU. References: [1]C. Froese Fischer, G. Tachiev, G. Gaigalas, M.R. Godefroid, An MCHF atomic-structure package for large-scale calculation, Comput. Phys. Commun. 176 (2007) 559-579. © 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{BorgooScharfGaigalasEtAl2010,
  author = {Borgoo, A. and Scharf, O. and Gaigalas, G. and Godefroid, M.},
  title = {Multiconfiguration electron density function for the ATSP2K-package},
  journal = {Computer Physics Communications},
  year = {2010},
  volume = {181},
  pages = {426-439},
  doi = {10.1016/j.cpc.2009.10.014}
}
BibTeX:
@article{BotschwinaHandyHalonenEtAl1988,
  author = {Botschwina, P. and Handy, N.C. and Halonen, L. and Gaw, J.F. and Ha, T.K. and Lewerenz, M. and Quack, M. and Sheppard, N. and Duncan, J.L. and Brodersen, S. and Baggott, J.E. and Law, D.W. and Lehmann, K.K. and Hutchinson, J.S. and Winnewisser, M. and Holme, T.A. and Carney, G.D. and Duxbury, G. and Tennyson, J. and Child, M.S. and Chambers, A.V. and Sutcliffe, B.T. and Jensen, P. and Marquardt, R. and Newnham, D.A. and Henry, B.R. and Mills, I.M. and Coy, S.L. and Caldow, G.L. and Smith, A.M. and Walsh, R. and Ashfold, M.N.R. and McKean, D.C. and Watts, R.O. and Carrasquillo, E. and Utz, A.L. and Crim, F.F. and Temps, F. and Santamaría, J. and Getino-Gonzalez, C. and Ezra, G.S. and Simons, J.P. and García-Ayllón, A. and Levine, R.D.},
  title = {General discussion},
  journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics},
  year = {1988},
  volume = {84},
  pages = {1555-1642},
  doi = {10.1039/F29888401555}
}
Abstract: The far infrared spectrum of methane is observed in emission in the stratosphere of Titan, Saturn's main satellite, allowing to determine its concentration in this environment. However this spectrum, which has a very low intensity because it is induced by the centrifugal distortion of the molecule only, was poorly characterized up to now. For the first time, it has been recorded, in absorption and at high resolution, at the AILES beamline of the SOLEIL synchrotron. Measurements have been performed for both pure methane and methanenitrogen mixtures. The intensities of methane lines and coefficients characterizing the broadening of these lines induced by collisions with nitrogen have been accurately determined. These new spectroscopic data, essential to analyze measurements in planetology, will most probably improve our understanding of physicochemical processes in planetary atmospheres where methane is often present.
BibTeX:
@article{BoudonGabardPiraliEtAl2011,
  author = {Boudon, V. and Gabard, T. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Vander Auwera, J. and Coustenis, A. and Lellouch, E.},
  title = {The far infrared spectrum of methane in the Titan's atmosphere [Le spectre infrarouge lointain du méthane dans l'atmosphère de Titan]},
  journal = {Actualite Chimique},
  year = {2011},
  pages = {97-99}
}
Abstract: The germane molecule, GeH4, is present in the atmospheres of giant planets Jupiter and Saturn. The ongoing NASA mission Juno has renewed interest in its spectroscopy, whose accurate modeling is essential for the retrieval of other tropospheric species. We present here the first complete analysis and modeling of line positions and intensities in the strongly absorbing ν1/ν3 stretching dyad region near 2100 cm−1, for all five germane isotopologues in natural abundance. New infrared spectra were recorded, absolute intensities were extracted through a careful procedure and modeled thanks to the formalism and programs developed in the Dijon group. A database of calculated germane lines, GeCaSDa, has been build and is available online through the Virtual Atomic and Molecular Data Centre (VAMDC) portal and at http://vamdc.icb.cnrs.fr/PHP/gecasda.php. © 2017 Elsevier Ltd
BibTeX:
@article{BoudonGrigoryanPhilipotEtAl2018,
  author = {Boudon, V. and Grigoryan, T. and Philipot, F. and Richard, C. and Tchana, F.K. and Manceron, L. and Rizopoulos, A. and Auwera, J.V. and Encrenaz, T.},
  title = {Line positions and intensities for the ν3 band of 5 isotopologues of germane for planetary applications},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2018},
  volume = {205},
  pages = {174-183},
  doi = {10.1016/j.jqsrt.2017.10.017}
}
Abstract: The Fourier transform infrared spectrum of SF6 was recorded in a supersonic expansion jet of an SF6/argon mixture. The SF6: Ar seeding ratio was 2:3. The instrumental bandwidth was 0.005 cm-1. A globar source and an MCT detector were used. A rotational temperature of approximately 30 K was achieved. The ν2 + ν6 combination band of 32SF6 was analyzed using a modified version of the spherical top data system (STDS) programs developed in Dijon. A very good fit was obtained for this band with an rms of 0.0036 cm-1. The effective Hamiltonian was developed up to fourth order for the ν2 + ν6 part, to second order for the ν2 and ground state parts, and to first order for the ν6 part. Five hundred twenty-one transitions were assigned, 40 of them reaching the F2u forbidden sublevel. The positions of the two F1u and F2u sublevels are found to be 991.276 and 989.487 cm-1, respectively. The ν3 band of the 33SF6 and 34SF6 isotopomers were also analyzed. Parameters and simulations are presented. A first detection of the ν3 Q branch of 36SF6 (0.02% natural abundance) is reported. © 1998 Academic Press.
BibTeX:
@article{BoudonHeppHermanEtAl1998,
  author = {Boudon, V. and Hepp, M. and Herman, M. and Pak, I. and Pierre, G.},
  title = {High-Resolution Jet-Cooled Spectroscopy of SF6: The ν2 + ν6 Combination Band of 32SF6 and the ν3 Band of the Rare Isotopomers},
  journal = {Journal of Molecular Spectroscopy},
  year = {1998},
  volume = {192},
  pages = {359-367},
  doi = {10.1006/jmsp.1998.7699}
}
Abstract: As a tetrahedral molecule, methane has no permanent dipole moment. Its spectrum, however, displays faint absorption lines in the THz region, due to centrifugal distorsion effects. This is important for planetary applications since this region is used to measure methane concentration in some planetary atmospheres, in particular on Titan. Up to now, all measurements relied either on some old low resolution infrared absorption spectra, or on high resolution Stark measurements for low J values only. Even if these results have been reexamined recently [Wishnow EH, Orton GS, Ozier I, Gush HP. The distorsion dipole rotational spectrum of CH4: a low temperature far-infrared study. J Quant Spectrosc Radiat Transfer 2007;103:102-17], it seemed highly desirable to obtain much more precise laboratory data.The high-intensity synchrotron radiation, combined with a 151.75±0.1m optical path in a White cell and a Bruker IFS 125 HR FTIR spectrometer at the AILES beamline of SOLEIL, enabled us to record this very weak spectrum at high resolution for the first time. Spectra were obtained in the 50-500cm-1 wavenumber range at 296K and 9.91, 20, 50 and 100mbar with a resolution of 0.00074, 0.00134, 0.0034 and 0.0067cm-1 (FWHM of the sinc function), respectively. The rotational clusters are fully resolved and the good signal-to-noise ratio has enabled precise measurements of transition intensities (92 cold band lines and 96 Dyad-Dyad hot band lines, with normal abundance intensities in the range 2×10-26-1×10-24cm-1/(molcm-2)), yielding an accurate determination of the dipole moment derivatives. Such results should allow a better determination of CH4 concentration in planetary objects. © 2010 Elsevier Ltd.
BibTeX:
@article{BoudonPiraliRoyEtAl2010,
  author = {Boudon, V. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Vander Auwera, J.},
  title = {The high-resolution far-infrared spectrum of methane at the SOLEIL synchrotron},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {1117-1129},
  doi = {10.1016/j.jqsrt.2010.02.006}
}
BibTeX:
@article{BoudonSearsCoheur2018,
  author = {Boudon, V. and Sears, T. and Coheur, P.-F.},
  title = {Introduction to the special issue on molecular spectroscopy, atmospheric composition and climate change},
  journal = {Journal of Molecular Spectroscopy},
  year = {2018},
  volume = {348},
  pages = {1},
  doi = {10.1016/j.jms.2018.04.005}
}
Abstract: The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0-10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores 2A1 and 2B1 results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the 2 B1 cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the 2A1 ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic characterization of vinylidene. © 2014 AIP Publishing LLC.
BibTeX:
@article{Boye-PeronneGauyacqLievin2014,
  author = {Boyé-Péronne, S. and Gauyacq, D. and Liévin, J.},
  title = {Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {141},
  article number = {174317},
  doi = {10.1063/1.4900875}
}
Abstract: The planar isomerization routes of the vinylidene/acetylene cation in the lowest electronic states are accurately examined for the first time, by using large scale MRCI and CCSD(T) calculations in a complementary way. They are compared with the similar calculations performed for the neutral ground state isomerization. An accurate value of the adiabatic ionization potential of vinylidene (11.26 eV) is predicted. The vinylidene cation lowest state, 1 A12, follows an almost flat pathway with a shallow secondary minimum on the 1 A′2 potential energy surface, before suddenly dropping to the stable acetylene cation ground state, X̃ Πu2. It is therefore confirmed to be completely unstable with respect to isomerization. The first excited state of the vinylidene cation, 1 B12, which also correlates with the Πu2 ground state of acetylene cation along a A′2 isomerization route, has been studied at the same level of calculation. This 1 B12 state is lying only 0.15 eV above the 1 A12 state, and exhibits a potential energy barrier of 0.55 eV which explains the earlier assignment of this symmetry to the ground state of vinylidene cation. In addition to large scale calculations, a comprehensive description of the important steps of isomerization drawn from a very simple model involving monoconfigurational states is presented. In particular, the behavior of one unique orbital, namely, the 5 a1 outer molecular orbital, is shown to completely govern the molecular geometry and energy evolution along the isomerization route of the ground state cation C2 H2+. © 2006 American Institute of Physics.
BibTeX:
@article{Boye-PeronneGauyacqLievin2006,
  author = {Boyé-Péronne, S. and Gauyacq, D. and Liévin, J.},
  title = {Vinylidene-acetylene cation isomerization investigated by large scale ab initio calculations},
  journal = {Journal of Chemical Physics},
  year = {2006},
  volume = {124},
  article number = {214305},
  doi = {10.1063/1.2187002}
}
Abstract: In this paper we investigate a severe pollution episode that occurred in Beijing, Tianjin, and the Hebei province in January 2013. The episode was caused by the combination of anthropogenic emissions and a high-pressure system that trapped pollutants in the boundary layer. Using IASI (Infrared Atmospheric Sounding Interferometer) satellite measurements, high concentrations of key trace gases such as carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3) along with ammonium sulfate aerosol ((NH 4)2SO4) are found. We show that IASI is able to detect boundary layer pollution in case of large negative thermal contrast combined with high levels of pollution. Our findings demonstrate that anthropogenic key pollutants, such as CO and SO2, can be monitored by IASI in the North China Plain during wintertime in support of air quality evaluation and management. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BoynardClerbauxClarisseEtAl2014,
  author = {Boynard, A. and Clerbaux, C. and Clarisse, L. and Safieddine, S. and Pommier, M. and Van Damme, M. and Bauduin, S. and Oudot, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F.},
  title = {First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: A case study in the North China Plain},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {645-651},
  doi = {10.1002/2013GL058333}
}
Abstract: In this paper, we present measurements of total and tropospheric ozone, retrieved from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which was launched on board the MetOp-A European satellite in October 2006. We compare IASI total ozone columns to Global Ozone Monitoring Experiment-2 (GOME-2) observations and groundbased measurements from the Dobson and Brewer network for one full year of observations (2008). The IASI total ozone columns are shown to be in good agreement with both GOME-2 and ground-based data, with correlation coefficients of about 0.9 and 0.85, respectively. On average, IASI ozone retrievals exhibit a positive bias of about 9DU (3.3%) compared to both GOME-2 and ground-based measurements. In addition to total ozone columns, the good spectral resolution of IASI enables the retrieval of tropospheric ozone concentrations. Comparisons of IASI tropospheric columns to 490 collocated ozone soundings available from several stations around the globe have been performed for the period of June 2007-August 2008. IASI tropospheric ozone columns compare well with sonde observations, with correlation coefficients of 0.95 and 0.77 for the [surface-6 km] and [surface-12 km] partial columns, respectively. IASI retrievals tend to overestimate the tropospheric ozone columns in comparison with ozonesonde measurements. Positive average biases of 0.15DU (1.2%) and 3DU (11%) are found for the [surface-6 km] and for the [surface-12 km] partial columns respectively. © 2009 Author(s).
BibTeX:
@article{BoynardClerbauxCoheurEtAl2009,
  author = {Boynard, A. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Turquety, S. and George, M. and Hadji-Lazaro, J. and Keim, C. and Meyer-Arnek, J.},
  title = {Measurements of total and tropospheric ozone from IASI: Comparison with correlative satellite, ground-based and ozonesonde observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6255-6271},
  doi = {10.5194/acp-9-6255-2009}
}
Abstract: This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2±0.8%. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ±2% over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6% with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4% in the midlatitudes and tropics and 7% at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30km) shows that on average IASI with FORLI processing underestimates O3 by ∼ 5-15% in the troposphere while it overestimates O3 by ∼ 10-40% in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated to cover a larger spectral range using the latest HITRAN spectroscopic database (HITRAN 2012) and implementing numerical corrections. The assessment of the new O3 product with the same set of observations as that used for the validation exercise shows a correction of ∼ 4% for the TOC positive bias when compared to the UV ground-based and satellite observations, bringing the overall global comparison to ∼ 1-2% on average. This improvement is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30hPa/25km) as shown by the comparison with ozonesonde data. © Author(s) 2016.
BibTeX:
@article{BoynardHurtmansKoukouliEtAl2016,
  author = {Boynard, A. and Hurtmans, D. and Koukouli, M.E. and Goutail, F. and Bureau, J. and Safieddine, S. and Lerot, C. and Hadji-Lazaro, J. and Wespes, C. and Pommereau, J.-P. and Pazmino, A. and Zyrichidou, I. and Balis, D. and Barbe, A. and Mikhailenko, S.N. and Loyola, D. and Valks, P. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C.},
  title = {Seven years of IASI ozone retrievals from FORLI: Validation with independent total column and vertical profile measurements},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {4327-4353},
  doi = {10.5194/amt-9-4327-2016}
}
Abstract: We present calculations of autoionization widths using a fully numerical multiconfigurational Hartree-Fock method (mchf). Energy positions and autoionization rates are given for several doubly-excited states lying below the n = 2 threshold in He [and H˜. Particular attention is given to orthogonality considerations in the computation of the autoionization widths. The method is extended to the ls2p2 2D, ls2s(3S)3d 2D and ls2s(3S)4d 2D states of Li 1. To the authors’ knowledge, our MCHF value, 12.5 meV, is the first result obtained for the autoionization width of the ls2s(3S)4d 2D state. Comparison is made with other theoretical results and with experimental values and we point out several inconsistencies between the two sets of results. © 1993 IOP Publishing Ltd.
BibTeX:
@article{BrageFischerVaeck1993,
  author = {Brage, I. and Fischer, C.F. and Vaeck, N.},
  title = {Mchf calculations of autoionization widths in two- and three-electron systems},
  journal = {Journal of Physics D: Applied Physics},
  year = {1993},
  volume = {26},
  pages = {621-640},
  doi = {10.1088/2015000624501X}
}
Abstract: We present calculations of autoionization widths using a fully numerical multiconfigurational Hartree-Fock method (mchf). Energy positions and autoionization rates are given for several doubly-excited states lying below the n = 2 threshold in He [and H-. Particular attention is given to orthogonality considerations in the computation of the autoionization widths. The method is extended to the ls2p2 2D, ls2s(3S)3d 2D and ls2s(3S)4d 2D states of Li 1. To the authors’ knowledge, our MCHF value, 12.5 meV, is the first result obtained for the autoionization width of the ls2s(3S)4d 2D state. Comparison is made with other theoretical results and with experimental values and we point out several inconsistencies between the two sets of results. © 1993 IOP Publishing Ltd.
BibTeX:
@article{BrageFischerVaeck1993a,
  author = {Brage, I. and Fischer, C.F. and Vaeck, N.},
  title = {Mchf calculations of autoionization widths in two- and three-electron systems},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1993},
  volume = {26},
  pages = {621-640},
  doi = {10.1088/0953-4075/26/4/006}
}
Abstract: The effect of core polarization on binding energies, term splitting, fine structure, and transition probabilities is investigated for the low lying states 4s2S, 3d2D, 4p2P° in Ca II and 4s2‘S, 4s4p1'3P° in Ca I. Results from inclusions of core polarization in the form of model potentials are com­pared with explicit MCHF calculations, and the accuracy of the different approaches is discussed. © 1993 IOP Publishing Ltd.
BibTeX:
@article{BrageFischerVaeckEtAl1993,
  author = {Brage, T. and Fischer, C.F. and Vaeck, N. and Godefroid, M. and Hibbert, A.},
  title = {Core polarization in ca i and ca ii},
  journal = {Physica Scripta},
  year = {1993},
  volume = {48},
  pages = {533-545},
  doi = {10.1088/0031-8949/48/5/006}
}
Abstract: The J = 0 → J′ = 0 radiative transitions, usually viewed as allowed through two-photon decay, may also be induced by the hyperfine (HPF) interaction in atoms or ions having a nonzero nuclear spin. We compute new and review existing decay rates for the nsnp 3PJo → ns2 1SJ′ = 0 transitions in ions of the Be (n = 2) and Mg (n = 3) isoelectronic sequences. The HPF induced decay rates for the J = 0 → J′ = 0 transitions are many orders of magnitude larger than those for the competing two-photon processes, and when present are typically 1 or 2 orders of magnitude smaller than the decay rates of the magnetic quadrupole (J = 2 → J′ = 0) transitions for these ions. Several HPF induced transitions are potentially of astrophysical interest in ions of C, N, Na, Mg, Al, Si, K, Cr, Fe, and Ni. We highlight those cases that may be of particular diagnostic value for determining isotopic abundance ratios and/or electron densities from UV or EUV emission-line data. We present our atomic data in the form of scaling laws so that, given the isotopic nuclear spin and magnetic moment, a simple expression yields estimates for HPF induced decay rates. We examine some UV and EUV solar and nebular data in light of these new results and suggest possible applications for future study. We could not find evidence for the existence of HPF induced lines in the spectra we examined, but we demonstrate that existing data have come close to providing interesting upper limits. For the planetary nebula SMC N2, we derive an upper limit of 0.1 for 13C/12C from Goddard High-Resolution Spectrograph data obtained by Clegg. It is likely that more stringent limits could be obtained using newer data with higher sensitivities in a variety of objects. © 1998. The American Astronomical Society. All rights reserved.
BibTeX:
@article{BrageJudgeAboussaidEtAl1998,
  author = {Brage, T. and Judge, P.G. and Aboussaïd, A. and Godefroid, M.R. and Jönsson, P. and Ynnerman, A. and Fischer, C.F. and Leckrone, D.S.},
  title = {Hyperfine induced transitions as diagnostics of isotopic composition and densities of low-density plasmas},
  journal = {Astrophysical Journal},
  year = {1998},
  volume = {500},
  pages = {507-521},
  doi = {10.1086/305690}
}
BibTeX:
@article{BramleyHendersonTennysonEtAl1993,
  author = {Bramley, M.J. and Henderson, J.R. and Tennyson, J. and Sutcliffe, B.T.},
  title = {On the Meyer-Botschwina-Burton potential energy surface for H 3+},
  journal = {The Journal of Chemical Physics},
  year = {1993},
  volume = {98},
  pages = {10104-10105},
  doi = {10.1063/1.464402}
}
Abstract: The transition between the diabatic and the adiabatic zero order representation when the electronic potential coupling increases, is studied in the partitioning method (PM) and in the complex coordinate method (CCM) implemented in a discrete variable representation (DVR). The model is a C+ type predissociation in a diatomic system with a crossing between a Morse potential energy curve and an exponentially repulsive curve. In the weak coupling regime (isolated diabatic metastable states), both methods confirm the linear variation of the resonance widths with the strength of the electronic interaction, as expected in a perturbative treatment. When the coupling is large in the diabatic representation (strong overlap regime), the formation of narrow resonances supported by the upper adiabatic potential can be related, in PM, to the process of avoided resonance overlapping among interfering states. The complete change of representation can be described in the initial diabatic basis set in PM. However, the full energy dependence of the discrete-continuous matrix elements must then be taken into account. The deformation and the final splitting of a diffuse spectral line .with increasing coupling is re-examined in terms of these energy dependent eigenvalues of the effective Hamiltonian. The use of the appropriate representation, either diabatic or adiabatic, according to the strength of the electronic coupling, has been found decisive in CCM so as to observe the correct migration of the resonance positions towards the zero order adiabatic states, and the decrease of their widths. No relevant results have been obtained for the intermediate strength of the coupling in CCM. Analytical expressions for the derivative coupling matrix elements (∂/∂R) in the fixed node DVR (corresponding to the particle-in-a-box wave functions) have been established. © 1996 American Institute of Physics.
BibTeX:
@article{BremsDesouter-LecomteLievin1996,
  author = {Brems, V. and Desouter-Lecomte, M. and Liévin, J.},
  title = {Avoided resonance overlapping beyond the energy independent formalism. II. Electronic predissociation},
  journal = {Journal of Chemical Physics},
  year = {1996},
  volume = {104},
  pages = {2222-2236},
  doi = {10.1063/1.470919}
}
Abstract: Volcanic eruptions emit plumes of ash and gases into the atmosphere, potentially at very high altitudes. Ash-rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever-increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be), which is a free online service initiated by the European Space Agency (ESA) for the near-real-time (NRT) satellite monitoring of volcanic plumes of SO2 and ash. It combines data from three ultraviolet (UV)-visible and three infrared (IR) spectrometers. The UV-vis sensors are the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the two polar orbiting meteorological satellites (MetOp-A &amp; MetOp-B) operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The IR sensors are the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on-board MetOp-A &amp; MetOp-B. This new multi-sensor warning system of volcanic emissions is based on the selective detection of SO2 and ash. This system is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. A successful rate with more than 95% of notifications corresponding to true volcanic activity is obtained by the SACS system. copyright © Author(s) 2014.
BibTeX:
@article{BrenotTheysClarisseEtAl2014,
  author = {Brenot, H. and Theys, N. and Clarisse, L. and Van Geffen, J. and Van Gent, J. and Van Roozendael, M. and Van Der A, R. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Valks, P. and Hedelt, P. and Prata, F. and Rasson, O. and Sievers, K. and Zehner, C.},
  title = {Support to aviation control service (SACS): An online service for near-real-time satellite monitoring of volcanic plumes},
  journal = {Natural Hazards and Earth System Sciences},
  year = {2014},
  volume = {14},
  pages = {1099-1123},
  doi = {10.5194/nhess-14-1099-2014}
}
Abstract: An ab initio study of the electronic structure of several 22-electrons molecules is presented. The equilibrium geometries of their ground state are calculated at the SCF level using the 6-31G basis set and are found to be in good agreement with the experimental geometries. The dissociation process of these molecules leading to the isoelectronic products CO or N2 on the one hand and BH3, CH2, NH and O on the other hand is studied. The least-energy dissociation paths of the ground states determined at the SCF level are compared on the basis of electron density interactions. The dissociation energies corresponding to the two lowest dissociation channels are calculated. In these calculations, the correlation energy is taken into account using a non-variational method developed previously. The calculated values of dissociation energies are in good agreement with the existing experimental values. The results permit to predict values for HNCO, BH3CO and CH2N2 and to confirm the instability of BH3N2. © 1982 Springer-Verlag.
BibTeX:
@article{BreuletLievin1982,
  author = {Breulet, J. and Lievin, J.},
  title = {Comparative theoretical study of the dissociation process of the isoelectronic molecules BH3CO, CH2CO, HNCO, CO2 and BH3N2, CH2N2, HN3, N2O},
  journal = {Theoretica Chimica Acta},
  year = {1982},
  volume = {61},
  pages = {59-72},
  doi = {10.1007/BF00573865}
}
Abstract: A simplified method of correlation energy calculation has been recently proposed (ref. 1-2). This method, which was shown to give good reaction heats where H.F. calculation fails (dissociations) is tested here in the calculation of reaction heats for which the H.F. approximation gives good results. © 1983.
BibTeX:
@article{BreuletxLievin1983,
  author = {Breuletx, J. and Lievin, J.},
  title = {Study of correlation effects in the calculation of heats of reactions.},
  journal = {Journal of Molecular Structure: THEOCHEM},
  year = {1983},
  volume = {93},
  pages = {341-345},
  doi = {10.1016/0166-1280(83)80123-7}
}
Abstract: We combine earlier treatments for the embedding of body-fixed coordinates in linear molecules with the close-coupling formalism developed for atom- diatom scattering and derive a hamiltonian which is most convenient for describing the nuclear motions in van der Waals complexes and other non-rigid Systems comprising two polyatomic fragments, A and B. This hamiltonian can stili be partitioned in the form Ha + Hb + HINT, just as the space-fixed hamiltonian. The body-fixed form, however, has several advantages. We discuss solution strategies for the rovibrational problem in non-rigid dimers, based on this partitioning of the hamiltonian. Finally, in view of the size of the generai polyatomic-polyatomic case, we suggest problems which should be currently practicable. © 1983 Taylor & Francis Group, LLC.
BibTeX:
@article{BrocksVanDerAvoirdSutcliffeEtAl1983,
  author = {Brocks, G. and Van Der Avoird, A. and Sutcliffe, B.T. and Tennyson, J.},
  title = {Quantum dynamics of non-rigid systems comprising two polyatomic fragments},
  journal = {Molecular Physics},
  year = {1983},
  volume = {50},
  pages = {1025-1043},
  doi = {10.1080/00268978300102831}
}
Abstract: Measurements of threshold crrent density and external efficiency on broad-area laser-waveguide structure have led to the determination of the optical loss and differential loss dx/dN ≃ 1.1-2.3 × 10-17cm2 at λ = 1.53µm in λg = 1.30µm GaInAsP layer. This measurement will be useful for the design of tunable lasers. © 1989, The Institution of Electrical Engineers. All rights reserved.
BibTeX:
@article{BrossonLabourieLeGouezigouEtAl1989,
  author = {Brosson, P. and Labourie, C. and Le Gouezigou, L. and Lievin, J.L. and Jacquet, J. and Leblond, F. and Olivier, A. and Leclerc, D.},
  title = {Experimental Determination of Carrier-Induced Differential Loss in 2-Section GaInAsP/InP Laser-Waveguide},
  journal = {Electronics Letters},
  year = {1989},
  volume = {25},
  pages = {1623-1624},
  doi = {10.1049/el:19891087}
}
Abstract: Non-adiabatic calculations on the positronium ion have been performed using laboratory-fixed hyperspherical coordinates and numerical wavefunctions. Convergence properties show that more than 98% of the true energy can be recovered using modest basis sets by truncating the radial domain and carrying out self-consistent field iterations solely on K = 0 levels. It seems likely that such procedures will enable more complex systems to be studied without recourse to extremely large basis sets. © 1993 Taylor & Francis Group, LLC.
BibTeX:
@article{BurdenSutcliffe1993,
  author = {Burden, F.R. and Sutcliffe, B.T.},
  title = {Three-body calculations in laboratory-fixed hyperspherical coordinates: Convergence properties using numerical wavefunctions as applied to the positronium ion e-3},
  journal = {Molecular Physics},
  year = {1993},
  volume = {80},
  pages = {383-389},
  doi = {10.1080/00268979300102321}
}
Abstract: A molecular beam of PbS molecules was excited by a CW Ar+ laser in single and multimode operation. Fluorescence spectra induced by the 4880 AA line were recorded and four fluorescence series originating from the nu =7, 8 and 9 levels of the A0+ state were analysed. Using a pulsed dye laser, lifetimes of the nu =4, 5, 6, 7 and 8 level of the A0+ state, the nu =0, 1, 2 and 3 levels of the B1 state and the nu =21 level of the a1 state were measured. The electronic transition moments of the a-X, A-X and B-X transitions were calculated and the lifetimes of the a, A and B states of PbS are compared with those of PbO.
BibTeX:
@article{BurtinCarleerColinEtAl1980,
  author = {Burtin, B. and Carleer, M. and Colin, R. and Dreze, C. and Ndikumana, T.},
  title = {Laser-induced fluorescence of gaseous PbS},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1980},
  volume = {13},
  article number = {016},
  pages = {3783-3795},
  doi = {10.1088/0022-3700/13/19/016}
}
Abstract: Three new weak bands of 12C2H2 at 13473.69, 13493.87 and 13787.97 cm-1 have been recorded by intracavity laser absorption spectroscopy and rotationally analyzed. Their presence was anticipated, on the basis of the cluster model recently presented by Abbouti Temsamani and Herman. The band energies and upper rotational parameters are well reproduced. The comparison between predicted and observed relative band intensities, including those previously reported in the literature in the range investigated, is briefly discussed. © 1995.
BibTeX:
@article{CampargueAbboutiTemsamaniHerman1995,
  author = {Campargue, A. and Abbouti Temsamani, M. and Herman, M.},
  title = {The absorption spectrum of acetylene in the 2ν2 + 3ν3 region. A test of the cluster model},
  journal = {Chemical Physics Letters},
  year = {1995},
  volume = {242},
  pages = {101-105},
  doi = {10.1016/0009-2614(95)00711-C}
}
Abstract: The 3ν1 and 3ν1 + ν3 bands of propyne have been recorded at Doppler-limited resolution by Fourier transform spectroscopy and intracavity laser absorption spectroscopy, respectively. The two bands show a mostly unperturbed J rotational structure for each individual K subband. However, as a rule the K structure ordering is perturbed in overtone transitions of propyne and different effective parameters associated with each K subband have been determined. From the vibrational energy levels, a value of -6.6 cm-1 has been obtained for the χ13 cross anharmonicity in perfect agreement with the origins of the ν1 + ν3 and 2ν1 + ν3 combination bands estimated from the FTIR spectrum. Hot bands from the ν9 = 1 and ν10 = 1 levels associated with the 3ν1 + ν3 combination band have been partly rotationally analyzed and the retrieved values of χ39 and χ3,10 are in good agreement with literature values. Finally, the 4ν1 + ν9 - ν9 band centered at 12 636.6 cm-1 has been recorded by ICLAS. The red shift of this hot band relative to 4ν1 and the ΔBν, value are discussed in relation to the anharmonic interaction between the 4ν1 and 3ν1 + ν3 + ν5 levels. © 2000 Academic Press.
BibTeX:
@article{CampargueBertsevaGranerEtAl2000,
  author = {Campargue, A. and Bertseva, E. and Graner, G. and Herman, M.},
  title = {High-Resolution Absorption Spectroscopy of the 3ν1 and 3ν1 + ν3 Bands of Propyne},
  journal = {Journal of Molecular Spectroscopy},
  year = {2000},
  volume = {201},
  pages = {156-163},
  doi = {10.1006/jmsp.2000.8073}
}
Abstract: The rotationally resolved nv1 (n = 2 - 6) overtone transitions of the CH acetylenic stretching of propyne (CH3-C≡C-H) have been recorded by using Fourier transform spectroscopy (n = 2), various intracavity laser absorption spectrometers (n = 3, 4, and 6) and cavity ring down spectroscopy (CRDS) (n = 5). The 2v1, 3v1, and 6v1, bands exhibit a well-resolved and mostly unperturbed J-rotational structure, whose analysis is reported. The 5v1 band recorded by pulsed CRDS shows an unresolved rotational envelope. In the region of 12 700 cm-1, an anharmonic interaction is confirmed between 4v1 and 3v1 + v3 + v5. The band at a higher wave number in this dyad exhibits a partly resolved K-structure, whose analysis is reported. The mixing coefficient of the two interacting states is determined consistently using different procedures. The 1/35 anharmonic resonance evidenced in the 4v1 manifold induces weaker intensity borrowing from the 2v1 and 3v1 levels to the v1 + v3 + v5 and 2v1 + v3 + v5 level, respectively, which have been predicted and identified. Several hot bands around the 2v1, 3v1, and 3v1 + v3 + v5 bands arising from the v9 = 1 and v10= 1 and 2 bending levels are identified and rotationally analyzed, also leading to determine x1,9 [-20.3(3) cm-1], x1,10 [-1.7975(75) cm-1], and x3,10 [-6.56 cm-1]. The J-clumps of the P and R branches in the 6v1 band at 18 499 cm-1 show a Lorentzian homogeneous profile mostly J-independent with an average full width at half maximum (FWHM) of 0.17 cm-1, attributed to arising from the intramolecular vibrational energy redistribution towards the bath of vibrational states. A detailed comparative examination of the fine structure in all investigated nv1 (n = 2 to 7) overtone bands and the similar behavior of the cold and hot bands arising from v10= 1 definitively suggests that a highly specific low-order anharmonic coupling, still unidentified, dominates the hierarchy of interaction mechanisms connecting the nv1 levels to the background states. © 1999 American Institute of Physics.
BibTeX:
@article{CampargueBiennierGarnacheEtAl1999,
  author = {Campargue, A. and Biennier, L. and Garnache, A. and Kachanov, A. and Romanini, D. and Herman, M.},
  title = {High resolution absorption spectroscopy of the v1 = 2 - 6 acetylenic overtone bands of propyne: Spectroscopy and dynamics},
  journal = {Journal of Chemical Physics},
  year = {1999},
  volume = {111},
  pages = {7888-7903},
  doi = {10.1063/1.480124}
}
Abstract: The absorption spectrum of 12C2 H2 has been recorded at high resolution by intracavity laser absorption spectroscopy between 14 500 cm-1 and 17 000 cm-1. Among the 32 bands which have been rotationally analysed 15 are newly observed, and improved rovibrational parameters are obtained for the others. The new resulting set of 26 vibrational levels is assigned by extrapolating the cluster model built from lower energy data (Abbouti Temsamani, M., and Herman, M., 1995, J. chem. Phys., 102, 6371) which allows vibrational energies and Bv rotational constants to be predicted. Intensity features are also discussed. © 1998 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{CampargueBiennierHerman1998,
  author = {Campargue, A. and Biennier, L. and Herman, M.},
  title = {The visible absorption spectrum of 12C2 H2 III. The region 14500-17000 cm-1},
  journal = {Molecular Physics},
  year = {1998},
  volume = {93},
  pages = {457-469},
  doi = {10.1080/002689798169140}
}
Abstract: The near infrared and visible absorption spectrum of nitrous oxide 14N2 16O has been recorded by Fourier transform absorption spectroscopy, between 6500 and 11 000 cm-1, and by Intracavity Laser Absorption Spectroscopy, between 11700 and 15 000 cm -1. Nineteen new bands are observed and, altogether, 34 cold and 10 hot bands are rotationally analyzed. The related upper term values, vibrational assignments, and principal rotational constants, as well as the relative band intensities are quantitatively discussed in terms of the formation of vibrational clusters, on the basis of the effective Hamiltonian developed by J. L. Teffo, V. I. Perevalov and O. M. Lyulin [J. Mol. Spectrosc. 168, 390 (1994)]. © 1995 American Institute of Physics.
BibTeX:
@article{CamparguePermogorovBachEtAl1995,
  author = {Campargue, A. and Permogorov, D. and Bach, M. and Temsamani, M.A. and Auwera, J.V. and Herman, M. and Fujii, M.},
  title = {Overtone spectroscopy in nitrous oxide},
  journal = {The Journal of Chemical Physics},
  year = {1995},
  volume = {103},
  pages = {5931-5938},
  doi = {10.1063/1.470473}
}
Abstract: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with &lt;25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000-2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2. © 2010 .
BibTeX:
@article{CampionSalernoCoheurEtAl2010,
  author = {Campion, R. and Salerno, G.G. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Kazahaya, K. and Burton, M. and Caltabiano, T. and Clerbaux, C. and Bernard, A.},
  title = {Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2010},
  volume = {194},
  pages = {42-54},
  doi = {10.1016/j.jvolgeores.2010.04.010}
}
Abstract: The results of an intercomparison campaign of eight different long path UV-visible DOAS instruments measuring NO2, O3 and SO2 concentrations in a moderately polluted urban site are presented. For effective optical path lengths of 230 and 780 m the overall spread of these measurements (± 1 σ) are 5 x 1010, 6 x 1010 and 1 x 1010 molec·cm-3 (2.0, 2.4, and 0.4 ppb) for these molecules respectively when all instruments used a common set of absorption cross sections. The remaining differences are not completely random and the systematic differences are attributed to the different retrieval methods used for each instrument.
BibTeX:
@article{Camy-PeyretBergqvistGalleEtAl1996,
  author = {Camy-Peyret, C. and Bergqvist, B. and Galle, B. and Carleer, M. and Clerbaux, C. and Colin, R. and Fayt, C. and Goutail, F. and Nunes-Pinharanda, M. and Pommereau, J.P. and Hausmann, M. and Platt, U. and Pundt, I. and Rudolph, T. and Hermans, C. and Simon, P.C. and Vandaele, A.C. and Plane, J.M.C. and Smith, N.},
  title = {Intercomparison of instruments for tropospheric measurements using differential optical absorption spectroscopy},
  journal = {Journal of Atmospheric Chemistry},
  year = {1996},
  volume = {23},
  pages = {51-80},
  doi = {10.1007/BF00058704}
}
Abstract: Thirty four cold bands and 37 hot bands are reported from the high resolution FT absorption spectrum of 13 CH 12 CH, all leading to vibrational states located between 3800 and 6750cm -1 . Each band has been vibrationally assigned and rotationally analysed. The band centres and rotational constants are listed.
BibTeX:
@article{CaneFusinaTamassiaEtAl2006,
  author = {Cané, E. and Fusina, L. and Tamassia, F. and Fayt, A. and Herman, M. and Robert, S. and Auwera, J.V.},
  title = {The FT absorption spectrum of 13CH 12 CH: Rotational analysis of the vibrational states from 3800 to 6750cm -1},
  journal = {Molecular Physics},
  year = {2006},
  volume = {104},
  pages = {515-526},
  doi = {10.1080/00268970500428991}
}
Abstract: This paper is the first part of a series devoted to the ab initio calculation of some vibrational properties helpful in the interpretation of high resolution spectroscopy, atmospherical and astrophysical data.An ab initio method of calculation of the vibrational transition energies and dipole moment matrix elements is described and analyzed.The main features of this method are the resolution of both electronic and vibrational problems by analytical variational techniques and the representation of the potential energy and dipole moment hypersurfaces as Taylor’s series expansions in normal coordinates up to the fourth order.The dipole moment matrix elements are then evaluated by simple analytical formulae.In this first paper, some of the approximations inherent to the methodology are systematically analyzed on the basis of results obtained for diatomic molecules (BeH, HF, NH and NO) with a comparison to experimental and other theoretical results found in the literature.The dependence on the results of the effects of electrical and mechanical anharmonicities, electron correlation and basis set dependencies are investigated.The applicability of the method to small polyatomic systems is discussed in the second paper of this series, on the basis of test calculations on the water molecule. © 1992 IOP Publishing Ltd.
BibTeX:
@article{CantarellaCulottLievin1992,
  author = {Cantarella, E. and Culott, F. and Lievin, J.},
  title = {Ab initio calculation of vibrational dipole moment matrix elements.I.methods of calculation and diatomic test systems},
  journal = {Physica Scripta},
  year = {1992},
  volume = {46},
  pages = {489-501},
  doi = {10.1088/0031-8949/46/6/003}
}
Abstract: The sulfur electron affinities eA(S) are measured by photodetachment microscopy for the two isotopes S32 and S34 (16752.9753(41) and 16752.9776(85) cm-1, respectively). The isotope shift in the electron affinity is found to be more probably positive, eA(S34)-eA(S32) =+0.0023(70) cm -1, but the uncertainty allows for the possibility that it may be either "normal" [eA(S34) eA(S32)] or "anomalous" [eA(S34) &lt;eA(S32)]. The isotope shift is estimated theoretically using elaborate correlation models, monitoring the electron affinity and the mass polarization term expectation value. The theoretical analysis predicts a very large specific mass shift (SMS) that counterbalances the normal mass shift (NMS) and produces an anomalous isotope shift eA(S34)-eA(S32) =-0.0053(24) cm-1, field shift corrections included. The total isotope shift can always be written as the sum of the NMS (here +0.0169 cm-1) and a residual isotope shift (RIS). Since the NMS has nearly no uncertainty, the comparison between experimental and theoretical RIS is more fair. With respective values of -0.0146(70) cm-1 and -0.0222(24) cm-1, these residual isotope shifts are found to agree within the estimated uncertainties. © 2010 The American Physical Society.
BibTeX:
@article{CaretteDragScharfEtAl2010,
  author = {Carette, T. and Drag, C. and Scharf, O. and Blondel, C. and Delsart, C. and Froese Fischer, C. and Godefroid, M.},
  title = {Isotope shift in the sulfur electron affinity: Observation and theory},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2010},
  volume = {81},
  article number = {042522},
  doi = {10.1103/PhysRevA.81.042522}
}
Abstract: The isotope effects in Si- bound levels are studied using the multiconfiguration Hartree-Fock ab initio approach. Large-scale calculations are carried out for the 3p34So, 2Do, and 2Po multiplets of Si- and the 3p23P multiplet of Si. We predict an anomalous isotope shift on the electron affinity, dominated by the specific mass shift, with a value of -0.66(6) m-1 for the 30-28 isotope pair. We also report hyperfine-structure parameters for the studied multiplets. We provide the values of level electric-field gradients at the nucleus that could be of interest in a study of the metastable silicon isotopes. Relativistic corrections are estimated using nonrelativistic orbitals in the Breit-Pauli and fully relativistic frameworks. © 2014 American Physical Society.
BibTeX:
@article{CaretteGodefroid2014,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Theoretical study of the isotope effects on the detachment thresholds of Si-},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2014},
  volume = {89},
  article number = {052513},
  doi = {10.1103/PhysRevA.89.052513}
}
Abstract: Today, the electron affinity is experimentally well known for most of the elements and is a useful guideline for developing ab initio computational methods. However, the measurements of isotope shifts on the electron affinity are limited by both resolution and sensitivity. In this context, theory is of great help to further our knowledge and understanding of atomic structures, even though correlation plays a dominant role in negative ions' properties and, particularly, in the calculation of the specific mass shift contribution. This study solves the longstanding discrepancy between calculated and measured specific mass shifts on the electron affinity of chlorine (Berzinsh et al 1995 Phys. Rev. A 51 231). © 2013 IOP Publishing Ltd.
BibTeX:
@article{CaretteGodefroid2013,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Isotope shift on the chlorine electron affinity revisited by an MCHF/CI approach},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2013},
  volume = {46},
  article number = {095003},
  doi = {10.1088/0953-4075/46/9/095003}
}
Abstract: We present highly correlated multi-configuration Hartree-Fock (MCHF) calculations of the hyperfine structure of the 3p 5 2P o J levels of 33S - and 35, 37Cl. We obtain good agreement with observation. The hyperfine structure of the neutral sulphur 33S 3p 4 3P J lowest multiplet that has never been measured to the knowledge of the authors is also estimated theoretically. We discuss some interesting observations made on the description of the atomic core in MCHF theory. © 2011 IOP Publishing Ltd.
BibTeX:
@article{CaretteGodefroid2011,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Ab initio calculations of the 33S 3p 4 3P J and 33S -/ 37, 35Cl 3p 5 2P o J hyperfine structures},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2011},
  volume = {44},
  article number = {105001},
  doi = {10.1088/0953-4075/44/10/105001}
}
Abstract: This work is an ab initio study of the 2p34S3/2o, and 2D3/2,5/2o states of C- and 2p23P0,1,2, 1D2, and 1S0 states of neutral carbon. We use the multiconfiguration Hartree-Fock approach, focusing on the accuracy of the wave function itself. We obtain all C - detachment thresholds, including correlation effects to about 0.5%. Isotope shifts and hyperfine structures are calculated. The achieved accuracy of the latter is of the order of 0.1 MHz. Intraconfiguration transition probabilities are also estimated. © 2011 American Physical Society.
BibTeX:
@article{CaretteGodefroid2011a,
  author = {Carette, T. and Godefroid, M.R.},
  title = {Theoretical study of the C- 4S3/2o and 2D3/2,5/2o bound states and C ground configuration: Fine and hyperfine structures, isotope shifts, and transition probabilities},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2011},
  volume = {83},
  article number = {062505},
  doi = {10.1103/PhysRevA.83.062505}
}
Abstract: The hyperfine constants of the levels 2p 2 (3P)3s 4P J, 2p 2 (3P)3p 4P oJ and 2p 2 (3P)3p 4D oJ, deduced by Jennerich et al. [Eur. Phys. J. D 40, 81 (2006)] from the observed hyperfine structures of the transitions 2p 2 (3P)3s 4P J→ 2p2 (3P)3p 4P oJ and 2p 2 (3P)3s 4P J→ 2p 2 ( 3P)3p 4D oJ recorded by saturation spectroscopy in the near-infrared, strongly disagree with the ab initio values of Jönsson et al. [J. Phys. B: At. Mol. Opt. Phys. 43, 115006 (2010)]. We propose a new interpretation of the recorded weak spectral lines. If the latter are indeed reinterpreted as crossover signals, a new set of experimental hyperfine constants is deduced, in very good agreement with the ab initio predictions. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{CaretteNemouchiJoenssonEtAl2010,
  author = {Carette, T. and Nemouchi, M. and Jönsson, P. and Godefroid, M.},
  title = {Saturation spectra of low lying states of Nitrogen: Reconciling experiment with theory},
  journal = {European Physical Journal D},
  year = {2010},
  volume = {60},
  pages = {231-242},
  doi = {10.1140/epjd/e2010-00241-2}
}
Abstract: The hyperfine interaction constants of the 2p4(3P)3p 2D3/2,5/2o, 4D1/2-7/2o, and 4P1/2-5/2o levels in neutral fluorine are investigated theoretically. Large-scale calculations are carried out using the multiconfiguration Hartree-Fock (MCHF) and Dirac-Hartree-Fock (MCDHF) methods. In the framework of the MCHF approach, the relativistic effects are taken into account in the Breit-Pauli approximation using nonrelativistic orbitals. In the fully relativistic approach, the orbitals are optimized using the Dirac-Coulomb Hamiltonian with correlation models inspired by the nonrelativistic calculations. Higher-order excitations are captured through multireference configuration interaction calculations including the Breit interaction. In a third (intermediate) approach, the Dirac-Coulomb-Breit Hamiltonian matrix is diagonalized in a relativistic configuration space built with nonrelativistic MCHF radial functions converted into Dirac spinors using the Pauli approximation. The magnetic dipole hyperfine-structure constants calculated with the three relativistic models are consistent and reveal unexpectedly large effects of relativity for 2D5/2o, 4P3/2o, and 4P5/2o. The agreement with the few available experimental values is satisfactory. The strong J dependence of relativistic corrections on the hyperfine constants is investigated through the detailed analysis of the orbital, spin-dipole, and contact relative contributions calculated with the nonrelativistic magnetic dipole operator. © 2013 American Physical Society.
BibTeX:
@article{CaretteNemouchiLiEtAl2013,
  author = {Carette, T. and Nemouchi, M. and Li, J. and Godefroid, M.},
  title = {Relativistic effects on the hyperfine structures of 2p4(3P) 3p2Do,4Do, and 4Po in 19F i},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {88},
  article number = {042501},
  doi = {10.1103/PhysRevA.88.042501}
}
Abstract: A program to measure with the highest accuracy the line parameters of high resolution Fourier transform spectra recorded in the laboratory has been written. Tests of the accuracy of the calculated parameters have been performed by comparing the results of the analysis of the 2-0 band of CO and of the v3 + v4 band of CO2. The line position accuracy has been found to be 9×10-6 cm-1, and the line intensity accuracy is of the order of 1 % or better.
BibTeX:
@conference{Carleer2001,
  author = {Carleer, M.R.},
  title = {WSpectra: A Windows® program to measure accurately the line intensities of high resolution Fourier transform spectra},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2001},
  volume = {4168},
  pages = {337-342},
  doi = {10.1117/12.413851}
}
Abstract: Concentration measurements of trace gases in the atmosphere require the use of highly sensitive and precise techniques. The Fourier transform absorption spectroscopy technique is one of them heavily used for atmospheric measurements. It is currently used in all spectral regions, from the far-IR to the near-UV. The spectra recorded will be either fully resolved, showing well separated lines, or will only show absorption bands consisting of a great number of overlapping lines. The algorithm used to retrieve the concentrations of the atmospherically important molecules depends on this, as well as the resolution used to record the spectra. In both cases however, the instrumental function will modify the spectrum shape and has to be taken into account. In order to retrieve concentrations with the best possible accuracy, a thorough understanding of how the instrumental function affects line profiles or absorbances is essential.
BibTeX:
@conference{Carleer1999,
  author = {Carleer, Michel},
  title = {FTS line shapes and their importance in atmospheric measurements in the UV-Vis and the IR},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {1999},
  volume = {3821},
  pages = {70-87}
}
Abstract: Using flash photolysis and flash discharge techniques, 28 bands of the f1 Delta u-a1 Delta g transition of S2 were photographed at high resolution in absorption. Vibrational and rotational analysis of these bands was made. The observation of this system in absorption allows the a 1 Delta g state to be identified as arising from the ground state electronic configuration pi u4 pi g2. The predissociation occurring between the v=10 and v=11 levels of the f1 Delta u state is probably a c+ type predissociation caused by a repulsive 3 Delta u state.
BibTeX:
@article{CarleerColin1970,
  author = {Carleer, M. and Colin, R.},
  title = {The f1Δ u-a1Δ g band system of S2 in absorption},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1970},
  volume = {3},
  article number = {015},
  pages = {1715-1723},
  doi = {10.1088/0022-3700/3/12/015}
}
Abstract: A rotational analysis is performed on the 0-0 band of the so called C2 band system of antimony monofluoride. The results show that the band actually consits of two transitions designated as the f0+-X21 and e0--X21 transitions. © 1978.
BibTeX:
@article{CarleerColinJones1978,
  author = {Carleer, M. and Colin, R. and Jones, W.E.},
  title = {Rotational analysis of the (f0+, e0-)-X21 transition of the antimony monofluoride molecule},
  journal = {Journal of Molecular Spectroscopy},
  year = {1978},
  volume = {70},
  pages = {405-409},
  doi = {10.1016/0022-2852(78)90178-9}
}
Abstract: Concentration measurements of trace gases in the atmosphere require the use of highly sensitive and precise techniques. The UV-Visible DOAS technique is one of them heavily used for tropospheric measurements. In order to assess the advantages and drawbacks of using a Fourier transform spectrometer, we have built a DOAS optical setup based on a Bruker IFS 120M spectrometer. The characteristics and capabilities of this setup have been studied and compared to those of the more conventional grating based instruments during several intercomparison campaigns. The main advantages of the FTS are: (i) the existence of a reproducible and precise wavenumber scale, which greatly simplifies the algorithms used to analyse the atmospheric spectra; and (ii) the possibility to record large spectral regions at relatively high resolution, enabling the simultaneous detection of numerous chemical species with better discriminating properties. The main drawback, on the other hand, is due to the fact that an FTS records high frequency signals and does not have the signal integration capabilities of the CCD based grating spectrographs. The FTS therefore needs fairly large amounts of light and is limited to short to medium absorption pathlengths.
BibTeX:
@conference{CarleerColinVandaele1998,
  author = {Carleer, M. and Colin, R. and Vandaele, A.C.},
  title = {Using a Fourier transform spectrometer for tropospheric UV-Vis DOAS measurements},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {1998},
  volume = {3493},
  pages = {11-19}
}
Abstract: NO2 absorption cross-sections have been obtained at 220 K and 294 K at a resolution of 2 cm-1 from a series of spectra recorded with pure NO2 at pressures from 0.007 to 2 torr. The N2O4 absorption cross-section has been obtained at 220 K. The uncertainty in the NO2 cross-sections is estimated to be less than 3% for the spectral region below 40000 cm-1 at 294 K, 3% below 30000 cm-1 at 220 K. Temperature and pressure effects have been observed. Comparison with literature data show good agreement (± 2%) between 37500 and 20000 cm-1. O2 absorption spectra have been recorded at high (0.12 cm-1) and low (2 and 16 cm-1) resolution in the UV. A re-analysis of the three Herzberg band systems has been performed, extending the rotational assignment up to N'' = 31 and identifying several new vibrational bands. Determination of the integrated intensities and oscillator strengths of the bands has been performed. These values have been compared with data of the literature. Spectra recorded with increasing pressures of N2 or Ar show that the structured continuum overlapping the Herzberg bands cannot be explained by O2-O2 absorption, but comes from collision induced absorption (CIA). Low resolution spectra (2 and 16 cm-1) have also been recorded in the visible region in order to determine the (O2)2 absorption cross-section.
BibTeX:
@conference{CarleerFallyColinEtAl1998,
  author = {Carleer, M. and Fally, S. and Colin, R. and Jenouvrier, A. and Coquart, B. and Merienne, M.-F. and Vandaele, A.C. and Hermans, Ch.},
  title = {Fourier transform spectroscopy of atmospheric gases},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {1998},
  volume = {3493},
  pages = {94-103}
}
Abstract: The assignment of the resonant fluorescence induced by the AR+ laser lines in 14N16O2 is reported for the first time with the 4727 and 4765 Å laser lines and is further developed with the 4579 and 4965 Å laser lines. © 1986.
BibTeX:
@article{CarleerHermanAuweraEtAl1986,
  author = {Carleer, M. and Herman, M. and Auwera, J.V. and Van Roozendael, M.},
  title = {Ar+ laser-induced fluorescence in NO2},
  journal = {Chemical Physics Letters},
  year = {1986},
  volume = {127},
  pages = {13-18},
  doi = {10.1016/S0009-2614(86)80201-9}
}
Abstract: New long path length, high resolution, Fourier transform spectrometer measurements for water are presented. These spectra cover the near infrared, visible, and near ultraviolet regions and contain water transitions belonging to all polyads from 3v to 8v. Transitions in the range 13 100-21 400 cm-1 are analyzed using line lists computed using variational first-principles calculations. 2286 new transitions are assigned to H2 16O. These result in the observation of transitions in 15 new overtone and combination bands of water. Energy levels for these and other newly observed levels are presented. It is suggested that local mode rather than normal mode vibrational assignments are more appropriate for the vibrational states of water in polyads 4v and above. © 7999 American Institute of Physics.
BibTeX:
@article{CarleerJenouvrierVandaeleEtAl1999,
  author = {Carleer, M. and Jenouvrier, A. and Vandaele, A.-C. and Bemath, P.F. and Mérienne, M.F. and Colin, R. and Zobov, N.F. and Polyansky, O.L. and Tennyson, J. and Savin, V.A.},
  title = {The near infrared, visible, and near ultraviolet overtone spectrum of water},
  journal = {Journal of Chemical Physics},
  year = {1999},
  volume = {111},
  pages = {2444-2450},
  doi = {10.1063/1.479859}
}
Abstract: A flew isotope shift program, part of the mchf atomic structure package, has recently been written. The program calculates the isotope shift of an atomic level from multiconfiguration Hartree-Fock (mchf) or configuration interaction (Ci) wavefunctions and is specially designed to be used with very large ci expansions, for which angular data cannot be stored on disk. To explore the capacity of the program, large-scale isotope shift calculations have been performed for the 1s22s2S and Is22p2P levels in C tv and for the ls22s22p2 S, ls22s22p3s ‘P, ls22s22p2 3P and ls22s2p3 5S levels in C t. From the isotope shifts of these levels theMC-i2C isotope shifts were calculated for the Is22s2S-ls22p2P transition in C iv and for the Is22s22p2 1 S-ls22s22p3sJP and ls22s22p2 3P-!s22s2p3 5S transitions in C i. The calculated transition isotope shifts are in very good agreement with experimental values, available for the C i transitions. As a check on the overall quality of the wavefunctions, the hyperfine structure interaction constants were calculated for the levels in C tv. © 1995 IOP Publishing Ltd.
BibTeX:
@article{CarlssonJonssonGodefroidEtAl1995,
  author = {Carlsson, J. and Jonsson, P. and Godefroid, M.R. and Fischer, C.F.},
  title = {Accurate multiconfiguration hartree-fock calculations of isotope shifts in c i and c iv},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1995},
  volume = {28},
  pages = {3729-3740},
  doi = {10.1088/0953-4075/28/17/012}
}
Abstract: Satellite instruments have been providing measurements of global volcanic emissions of sulfur dioxide (SO2) since 1978, based on observations in the ultraviolet (UV), infrared (IR) and microwave spectral bands. We review recent advances in satellite remote sensing of volcanic gases, focusing on increased instrument sensitivity to tropospheric SO2 emissions and techniques to determine volcanic plume altitude. A synthesis of ~36 years of global UV, IR and microwave satellite measurements yields an updated assessment of the volcanic SO2 flux to the upper troposphere and lower stratosphere (UTLS) between 1978 and 2014 (~1-Tg/yr). The present availability of multiple UV and IR satellite SO2 products provides increased confidence in calculated SO2 loadings for many eruptions. We examine the temporal and latitudinal distribution of volcanic SO2 emissions and reassess the relationship between eruptive SO2 discharge and eruption magnitude, finding a first-order correlation between SO2 emission and volcanic explosivity index (VEI), but with significant scatter. Based on the observed SO2-VEI relation, we estimate the fraction of eruptive SO2 emissions released by the smallest eruptions (~0.48 Tg/yr), which is not recorded by satellite observations. A detailed breakdown of the sources of measured SO2 emissions reveals intuitively expected correlations between eruption frequency, SO2 loading and volcanic degassing style. We discuss new constraints on e-folding times for SO2 removal in volcanic plumes, and highlight recent measurements of volcanic hydrogen chloride (HCl) injections into the UTLS. An analysis of passive volcanic emissions of SO2 detected in Ozone Monitoring Instrument (OMI) SO2 data since 2004 provides new insight into the location and stability of the dominant sources of volcanic SO2 over the past decade. Since volcanic SO2 emissions constitute a random, highly variable perturbation to the atmosphere-climate system, continued monitoring of volcanic SO2 emissions from space by multiple UV and IR instruments to extend the current multi-decadal record is essential, and near-global, geostationary measurements of SO2 may be available by the end of the current decade. © 2016 The Authors.
BibTeX:
@article{CarnClarissePrata2016,
  author = {Carn, S.A. and Clarisse, L. and Prata, A.J.},
  title = {Multi-decadal satellite measurements of global volcanic degassing},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2016},
  volume = {311},
  pages = {99-134},
  doi = {10.1016/j.jvolgeores.2016.01.002}
}
BibTeX:
@article{CarterHandySutcliffe1983,
  author = {Carter, S. and Handy, N.C. and Sutcliffe, B.T.},
  title = {Preliminary communication: A variational method for the calculation of rovibrational levels of any triatomic molecule},
  journal = {Molecular Physics},
  year = {1983},
  volume = {49},
  pages = {745-748},
  doi = {10.1080/00268978300101521}
}
Abstract: Benchmark first principles calculations of the pure rotational and ro-vibrational transition frequencies and line strengths are presented, using two independent program suites. Both sets of calculations were performed using the same potential energy and dipole surfaces. Our example calculations use recently calculated surfaces for H2S which have been shown to give good agreement with experimental data. The results, which show perfect agreement for the energy levels, transition frequencies and line strengths, are used as an external check on the two program suites. It is suggested they could provide a standard with which other groups working in this field can compare their calculations. © 1989.
BibTeX:
@article{CarterRosmusHandyEtAl1989,
  author = {Carter, S. and Rosmus, P. and Handy, N.C. and Miller, S. and Tennyson, J. and Sutcliffe, B.T.},
  title = {Benchmark calculations of first principles rotational and ro-vibrational line strenghts},
  journal = {Computer Physics Communications},
  year = {1989},
  volume = {55},
  pages = {71-75},
  doi = {10.1016/0010-4655(89)90064-7}
}
Abstract: In a previous article a dipole moment surface (DMS) of full-electron, multi-reference configuration interaction (MRCI) quality was obtained and used to calculate the rotational spectrum of methane vibrational ground state, by means of a combination of the mean field configuration interaction method (VMFCI) with a generalized perturbation theory. The theoretical line intensities were matching the experimental ones obtained at the SOLEIL synchrotron well within experimental uncertainties. However, not all third order terms were included in this DMS. In the present work, additional DMS points have been calculated and fitted using a complete third order expansion. The new results give R-branch intensities systematically smaller by about 1% compared to those previously obtained by using the same ab initio method, so still within experimental errors. The relevance of this DMS to calculate intensities for excited vibrational states, in particular for the dyad, is addressed. © 2013 Elsevier Inc. All rights reserved.
BibTeX:
@article{Cassam-ChenaiLievin2013,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {An improved third order dipole moment surface for methane},
  journal = {Journal of Molecular Spectroscopy},
  year = {2013},
  volume = {291},
  pages = {77-84},
  doi = {10.1016/j.jms.2013.07.004}
}
Abstract: In a previous article we have introduced an alternative perturbation scheme to the traditional one starting from the harmonic oscillator, rigid rotator Hamiltonian, to find approximate solutions of the spectral problem for rotation-vibration molecular Hamiltonians. The convergence of our method for the methane vibrational ground state rotational energy levels was quicker than that of the traditional method, as expected, and our predictions were quantitative. In this second article, we study the convergence of the ab initio calculation of effective dipole moments for methane within the same theoretical frame. The first order of perturbation when applied to the electric dipole moment operator of a spherical top gives the expression used in previous spectroscopic studies. Higher orders of perturbation give corrections corresponding to higher centrifugal distortion contributions and are calculated accurately for the first time. Two potential energy surfaces of the literature have been used for solving the anharmonic vibrational problem by means of the vibrational mean field configuration interaction approach. Two corresponding dipole moment surfaces were calculated in this work at a high level of theory. The predicted intensities agree better with recent experimental values than their empirical fit. This suggests that our ab initio dipole moment surface and effective dipole moment operator are both highly accurate. © 2012 American Institute of Physics.
BibTeX:
@article{Cassam-ChenaiLievin2012,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {Ab initio calculation of the rotational spectrum of methane vibrational ground state},
  journal = {Journal of Chemical Physics},
  year = {2012},
  volume = {136},
  article number = {174309},
  doi = {10.1063/1.4705278}
}
Abstract: The present article introduces a general variational scheme to find approximate solutions of the spectral problem for the molecular vibration Hamiltonian. It is called the "vibrational mean field configuration interaction" (VMFCI) method, and consists in performing vibrational configuration interactions (VCI) for selected modes in the mean field of the others. The same partition of modes can be iterated until self-consistency, generalizing the vibrational self-consistent field (VSCF) method. As in contracted-mode methods, a hierarchy of partitions can be built to ultimately contract all the modes together. So, the VMFCI method extends the traditional variational approaches and can be included in existing vibrational codes based on the latter approaches. The flexibility and efficiency of this new method are demonstrated on several molecules of atmospheric interest. © 2006 Wiley Periodicals, Inc.
BibTeX:
@article{Cassam-ChenaiLievin2006,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {The VMFCI method: A flexible tool for solving the molecular vibration problem},
  journal = {Journal of Computational Chemistry},
  year = {2006},
  volume = {27},
  pages = {627-640},
  doi = {10.1002/jcc.20374}
}
Abstract: This article introduces an alternative perturbation scheme to find approximate solutions of the spectral problem for the rotation-vibration molecular Hamiltonian. The method is implemented for the Watson Hamiltonian and applied to methane. The complete J = 0 spectrum of this penta-atomic molecule of atmospheric interest is calculated up to 9200 cm-1 in a purely ab initio fashion. Then, the rotational spectra of the vibrational ground state is obtained up to J = 18. The largest relative error is 2.10-5 (for the highest J = 18 level) after scaling of a single parameter. Without scaling the accuracy on the rotational levels is limited by that of the ab initio equilibrium bond distance. The convergence of our results is analyzed with respect to the different parameters involved in our approach. The important concept of vibrational mean-field configuration interaction is introduced.
BibTeX:
@article{Cassam-ChenaiLievin2003,
  author = {Cassam-Chenaï, P. and Liévin, J.},
  title = {Alternative perturbation method for the molecular vibration-rotation problem},
  journal = {International Journal of Quantum Chemistry},
  year = {2003},
  volume = {93},
  pages = {245-264},
  doi = {10.1002/qua.10556}
}
Abstract: The vibrational energy levels of fluoroform have been computed with and without the kinetic coupling terms of the Eckart-Watson Hamiltonian by using the vibrational mean field configuration interaction method. The results are well-converged as demonstrated by a comparison with those obtained with other variational methods when kinetic coupling is omitted. It is found that kinetic coupling is not negligible for this system. The wave number difference with and without kinetic coupling is 37 cm-1 for the ν1 (CH-stretching) fundamental transition and can be larger than 60 cm-1 in the ν1 s(-) ν4 (HCF bending) overtones. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{Cassam-ChenaiScribanoLievin2008,
  author = {Cassam-Chenaï, P. and Scribano, Y. and Liévin, J.},
  title = {Influence of kinetic coupling in rectilinear coordinates on the vibrational spectrum of fluoroform},
  journal = {Chemical Physics Letters},
  year = {2008},
  volume = {466},
  pages = {16-20},
  doi = {10.1016/j.cplett.2008.10.025}
}
Abstract: The charge transfer process in an ionized stacking of two consecutive guanines (G5'G3')+ has been studied by means of state-averaged CASSCF/MRCI and RASSCF/RASPT2 calculations. The ground and two first excited states of the radical cation have been characterized, and the topology of the corresponding potential energy surfaces (PESs) has been studied as a function of all intermolecular geometrical parameters. The results demonstrate that the charge transfer process in (G5'G 3')- is governed by the avoiding crossing between the ground and first excited states of the complex. Relative translation motions of both guanines in their molecular planes are shown to lead to the charge migration between G5' and G3'. Five stationary points (three minima and two saddle points) have been characterized along the reaction path describing the passage of the positive charge from G5' to G 3'. The global minimum on the PES is found to correspond to the charge configuration G5'+G3'. The existence of an intermediate minimum along the reaction path has been established, characterizing a structure where the positive charge is equally distributed between the two guanines. The calculated energy profile allowed us to determine the height of the potential energy barrier (7.33 kcal/mol) and to evaluate the electronic coupling at a geometry close to the avoiding crossing (3.6 kcal/mol). Test calculations showed that the topology of the ground state PES of the complex GG+ is qualitatively conserved upon optimization of the intramolecular geometrical parameters of the stationary points. © 2009 American Chemical Society.
BibTeX:
@article{CaueetLievin2009,
  author = {Cauëet, E. and Liévin, J.},
  title = {Ab initio study of the electron transfer in an ionized stacked complex of guanines},
  journal = {Journal of Physical Chemistry A},
  year = {2009},
  volume = {113},
  pages = {9881-9890},
  doi = {10.1021/jp902426p}
}
Abstract: Ab initio quantum mechanical methods provide microscopic insights into DNA characteristics and are, today, essential to the full interpretation and understanding of results obtained by experimental techniques. In this chapter we summarize the contributions of modern quantum chemicalcalculations to the determination of the electronic properties of DNA bases, isolated or embedded in base clusters. In particular, the calculations discussed concern the characterization of the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration along DNA molecules. We mainly consider the estimation of key parameters, such as ionization potentials (IPs) of DNA bases, which govern the charge injection into DNA. The effects of the stacking and H-bonding DNA base interactions and the solvation of DNA on these quantities are described. We also discuss the mechanisms of charge migration over stacked DNA bases. These aspects are illustrated by a survey of the literature and by our own selected recent results. © 2012 by Nova Science Publishers, Inc. All rights reserved.
BibTeX:
@book{Cauet2011,
  author = {Cauët, E.},
  title = {Quantum mechanical methods related to ionization of nucleic acid bases},
  journal = {DNA Microarrays, Synthesis and Synthetic DNA},
  year = {2011},
  pages = {255-284}
}
Abstract: The hypothetical protection of genes from oxidative damage provided by the G-rich telomeric overhangs located at the end of chromosomes, which consist, in humans, of single strands of TTAGGG sequence repeats, is investigated here. First principle Møller-Plesset perturbation theory calculations reveal that the TTAGGG human telomere sequence is particularly prone to oxidation and can act as a profound hole trap as deep as a sequence of five consecutive guanines. In addition, we show that the sequence dependence is very important and that modifications in the human telomeric sequence can induce crucial changes in the electronic structure of the sequence, with concomitant increase of the ionization energy. These theoretical results provide, for the first time, quantitative data indicating a high and unique efficiency of the human telomeric sequence as a trap in long-range hole migration which will aid in the design of subsequent experiments. © 2011 Taylor & Francis Group, LLC.
BibTeX:
@article{Cauet2011a,
  author = {Cauët, E.},
  title = {Unique hole-trapping property of the human telomere sequence},
  journal = {Journal of Biomolecular Structure and Dynamics},
  year = {2011},
  volume = {29},
  pages = {557-561},
  doi = {10.1080/07391102.2011.10507405}
}
Abstract: The Car-Parrinello-based molecular dynamics (CPMD) method was used to investigate the ion-pairing behavior between Cl - and Al 3+ ions in an aqueous AlCl 3 solution containing 63 water molecules. A series of constrained simulations was carried out at 300 K for up to 16 ps each, with the internuclear separation (r Al-Cl) between the Al 3+ ion and one of the Cl - ions held constant. The calculated potential of mean force (PMF) of the Al 3+-Cl - ion pair shows a global minimum at r Al-Cl = 2.3 Å corresponding to a contact ion pair (CIP). Two local minima assigned to solvent-separated ion pairs (SSIPs) are identified at r Al-Cl = 4.4 and 6.0 Å. The positions of the free energy minima coincide with the hydration-shell intervals of the Al 3+ cation, suggesting that the Cl - ion is inclined to reside in regions with low concentrations of water molecules, that is, between the first and second hydration shells of Al 3+ and between the second shell and the bulk. A detailed analysis of the solvent structure around the Al 3+ and Cl - ions as a function of r Al-Cl is presented. The results are compared to structural data from X-ray measurements and unconstrained CPMD simulations of single Al 3+ and Cl - ions and AlCl 3 solutions. The dipole moments of the water molecules in the first and second hydration shells of Al 3+ and in the bulk region and those of Cl - ions were calculated as a function of r Al-Cl. Major changes in the electronic structure of the system were found to result from the removal of Cl - from the first hydration shell of the Al 3+ cation. Finally, two unconstrained CPMD simulations of aqueous AlCl 3 solutions corresponding to CIP and SSIP configurations were performed (17 ps, 300 K). Only minor structural changes were observed in these systems, confirming their stability. © 2012 American Chemical Society.
BibTeX:
@article{CauetBogatkoBylaskaEtAl2012,
  author = {Cauët, E. and Bogatko, S.A. and Bylaska, E.J. and Weare, J.H.},
  title = {Ion association in AlCl 3 aqueous solutions from constrained first-principles molecular dynamics},
  journal = {Inorganic Chemistry},
  year = {2012},
  volume = {51},
  pages = {10856-10869},
  doi = {10.1021/ic301346k}
}
Abstract: Low energy electron-attachment-induced damage in DNA, where dissociation channels may involve multiple bonds including complex bond rearrangements and significant nuclear motions, is analyzed here. Quantum mechanics/molecular mechanics (QM/MM) calculations reveal how rearrangements of electron density after vertical electron attachment modulate the position and dynamics of the atomic nuclei in DNA. The nuclear motions involve the elongation of the P-O (P-O3′ and P-O5′) and C-C (C3′-C4′ and C4′-C5′) bonds for which the acquired kinetic energy becomes high enough so that the neighboring C3′-O3′ or C5′-O5′ phosphodiester bond may break almost immediately. Such dynamic behavior should happen on a very short time scale, within 15-30 fs, which is of the same order of magnitude as the time scale predicted for the excess electron to localize around the nucleobases. This result indicates that the C-O phosphodiester bonds can break before electron transfer from the backbone to the base. © 2013 American Chemical Society.
BibTeX:
@article{CauetBogatkoLievinEtAl2013,
  author = {Cauët, E. and Bogatko, S. and Liévin, J. and De Proft, F. and Geerlings, P.},
  title = {Electron-attachment-induced DNA damage: Instantaneous strand breaks},
  journal = {Journal of Physical Chemistry B},
  year = {2013},
  volume = {117},
  pages = {9669-9676},
  doi = {10.1021/jp406320g}
}
Abstract: The unprotonated and protonated monoreduced forms of the polyazaaromatic Ru(II) coordination complexes [Ru(tap)3]2+ and [Ru(tap)2(phen)]2+ (tap = 1,4,5,8-tetraazaphenanthrene; phen = 1,10-phenanthroline), that is, [Ru(tap)3]•+, [Ru(tap)2(phen)]•+, [Ru(tap)2(tap-H)] •2+, and [Ru(tap)(tap-H)(phen)]•2+, were studied by Density Functional Theory (DFT). The electron spin density of these radical cations, the isotropic Fermi-contact, and the anisotropic dipolar contributions to the hyperfine coupling constants of the H nuclei were calculated in vacuo and using a continuum model for water solvation. For [Ru(tap)2(phen)] •+, as well as for its protonated form, the DFT results show that the unpaired electron is not localized on the phen ligand. For both [Ru(tap)3]•+ and [Ru(tap)2(phen)] •+, they reveal high electron spin density in the vicinity of tap H-2 and tap H-7 (the H atoms in the ortho position of the tap non-chelating N atoms). These results are in full agreement with recent steady-state 1H photo-Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP) measurements. The DFT calculations performed for the protonated species also predict major 1H photo-CIDNP enhancements at these positions. Interestingly, they indicate significantly different polarization for tap H-9,10, suggesting that the occurrence of a photoinduced electron transfer with protonation of the reduced species might be detected by high-precision photo-CIDNP experiments. © 2010 American Chemical Society.
BibTeX:
@article{CauetBogatkoMugeniwabagaraEtAl2010,
  author = {Cauët, E. and Bogatko, S. and Mugeniwabagara, E. and Fusaro, L. and Kirsch-De Mesmaeker, A. and Luhmer, M. and Vaeck, N.},
  title = {Density functional theory interpretation of the 1H photo-chemically induced dynamic nuclear polarization enhancements characterizing photoreduced polyazaaromatic Ru(II) coordination complexes},
  journal = {Inorganic Chemistry},
  year = {2010},
  volume = {49},
  pages = {7826-7831},
  doi = {10.1021/ic100636j}
}
Abstract: Results of ab initio molecular dynamics (AIMD) simulations (density functional theory+PBE96) of the dynamics of waters in the hydration shells surrounding the Zn2+ ion (T≈300 K, ρ ≈1 gm/ cm3) are compared to simulations using a combined quantum and classical molecular dynamics [AIMD/molecular mechanical (MM)] approach. Both classes of simulations were performed with 64 solvating water molecules (∼15 ps) and used the same methods in the electronic structure calculation (plane-wave basis set, time steps, effective mass, etc.). In the AIMD/MM calculation, only six waters of hydration were included in the quantum mechanical (QM) region. The remaining 58 waters were treated with a published flexible water-water interaction potential. No reparametrization of the water-water potential was attempted. Additional AIMD/MM simulations were performed with 256 water molecules. The hydration structures predicted from the AIMD and AIMD/MM simulations are found to agree in detail with each other and with the structural results from x-ray data despite the very limited QM region in the AIMD/MM simulation. To further evaluate the agreement of these parameter-free simulations, predicted extended x-ray absorption fine structure (EXAFS) spectra were compared directly to the recently obtained EXAFS data and they agree in remarkable detail with the experimental observations. The first hydration shell contains six water molecules in a highly symmetric octahedral structure is (maximally located at 2.13-2.15 Å versus 2.072 Å EXAFS experiment). The widths of the peak of the simulated EXAFS spectra agree well with the data (8.4 Å2 versus 8.9 Å2 in experiment). Analysis of the H-bond structure of the hydration region shows that the second hydration shell is trigonally bound to the first shell water with a high degree of agreement between the AIMD and AIMD/MM calculations. Beyond the second shell, the bonding pattern returns to the tetrahedral structure of bulk water. The AIMD/MM results emphasize the importance of a quantum description of the first hydration shell to correctly describe the hydration region. In these calculations the full d10 electronic structure of the valence shell of the Zn2+ ion is retained. The simulations show substantial and complex charge relocation on both the Zn 2+ ion and the first hydration shell. The dipole moment of the waters in the first hydration shell is 3.4 D (3.3 D AIMD/MM) versus 2.73 D bulk. Little polarization is found for the waters in the second hydration shell (2.8 D). No exchanges were seen between the first and the second hydrations shells; however, many water transfers between the second hydration shell and the bulk were observed. For 64 waters, the AIMD and AIMD/MM simulations give nearly identical results for exchange dynamics. However, in the larger particle simulations (256 waters) there is a significant reduction in the second shell to bulk exchanges. © 2010 American Institute of Physics.
BibTeX:
@article{CauetBogatkoWeareEtAl2010,
  author = {Cauët, E. and Bogatko, S. and Weare, J.H. and Fulton, J.L. and Schenter, G.K. and Bylaska, E.J.},
  title = {Structure and dynamics of the hydration shells of the Zn2+ ion from ab initio molecular dynamics and combined ab initio and classical molecular dynamics simulations},
  journal = {Journal of Chemical Physics},
  year = {2010},
  volume = {132},
  article number = {194502},
  doi = {10.1063/1.3421542}
}
Abstract: We present a summary of the research activities of the "Quantum Chemistry and Atomic Physics" theoretical group of the "Chimie Quantique et Photophysique" Laboratory at Université Libre de Bruxelles. We emphasize the links between the three orientations of the group: theoretical atomic spectroscopy, structure, and molecular dynamics and list the perspectives of our collaboration. © Springer-Verlag 2012.
BibTeX:
@article{CauetCaretteLauzinEtAl2012,
  author = {Cauët, E. and Carette, T. and Lauzin, C. and Li, J.G. and Loreau, J. and Delsaut, M. and Nazé, C. and Verdebout, S. and Vranckx, S. and Godefroid, M. and Liévin, J. and Vaeck, N.},
  title = {From atoms to biomolecules: A fruitful perspective},
  journal = {Theoretical Chemistry Accounts},
  year = {2012},
  volume = {131},
  pages = {1-17},
  doi = {10.1007/s00214-012-1254-3}
}
Abstract: The ionization of the four DNA bases is investigated by means of ab initio calculations. Accurate values of the gas-phase vertical and adiabatic ionization potentials (IP) are obtained at the MP2/6-31G(2d(0.8,αd),p) level of theory. The need of introducing extra polarization to the standard 6-31G(d,p) basis set is demonstrated by test calculations and an optimal value of αd = 0.1 is obtained. Ionization to electronically excited radical cations is also considered. The low-lying excited states of the cations are characterized for the first time. The topology of the corresponding potential energy surfaces is qualitatively described in terms of the stationary points (minima and saddle points) located on these surfaces. A conical intersection is characterized for the first time on the ground-state potential energy surface of all cations. It arises from the crossing of the adiabatic surfaces of the ground and first excited state at planar geometries. A nonplanar minimum is observed for the cytosine cation only. The geometry and electronic changes occurring along these surfaces are analyzed, leading to a comparison between the different nucleobase cations. The study of larger ionized systems related to DNA is rendered possible thanks to the optimized medium size basis set proposed in this work, as exemplified by the calculation of the IP of a stacked dimer of guanines. © 2006 American Chemical Society.
BibTeX:
@article{CauetDeharengLievin2006,
  author = {Cauët, E. and Dehareng, D. and Liévin, J.},
  title = {Ab initio study of the lonization of the DNA bases: Ionization potentials and excited states of the cations},
  journal = {Journal of Physical Chemistry A},
  year = {2006},
  volume = {110},
  pages = {9200-9211},
  doi = {10.1021/jp0617625}
}
Abstract: Using Density Functional Theory approaches, we investigate the structure and spectroscopic signatures of sumanene, monooxosumanene and trioxosumanene, three synthesised bowl-shaped compounds. The simulated properties include geometries, charges, polarisabilities, infrared and UV/visible spectra as well as complexation energies. Refined approaches have been considered (anharmonic frequencies, state-specific solvent model, dispersion-corrected DFT...) and a valuable agreement with experimental reference values is reached for most properties. The evolution of the electronic features of sumanene upon oxidation has been rationalised. © 2011 Elsevier B.V. All rights reserved.
BibTeX:
@article{CauetJacquemin2012,
  author = {Cauët, E. and Jacquemin, D.},
  title = {A theoretical spectroscopy investigation of oxosumanenes},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {519-520},
  pages = {49-53},
  doi = {10.1016/j.cplett.2011.11.021}
}
Abstract: This review summarizes the contribution of high level quantum chemical calculations to the investigation of some elementary reactive processes related to the radiation damage to DNA. It is focused on the biomimetic species that govern these processes at the molecular level. These species are the DNA bases, isolated or embedded in base clusters. Their cations, formed by ionization in their ground and first excited electronic states, are at the center of the present work. We present a synthetic and critical overview of the computational methods used to predict accurate ionization potentials, to correctly describe the non-bonding interactions (stacking, H-bonding and cation-π) stabilizing the studied biomimetic clusters, to characterize their excited states and to investigate the topology of the corresponding potential energy surfaces (minima, transition states, avoided crossings, conical intersections, reaction paths). All these aspects are illustrated by the recent literature and by our own research work, namely on the electron transfer occurring within a stacked dimer of guanines. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{CauetLievin2007,
  author = {Cauët, E. and Liévin, J.},
  title = {Radical Cations of the Nucleic Bases and Radiation Damage to DNA: Ab Initio Study},
  journal = {Advances in Quantum Chemistry},
  year = {2007},
  volume = {52},
  pages = {121-147},
  doi = {10.1016/S0065-3276(06)52006-4}
}
Abstract: His-aromatic complexes, with the His located above the aromatic plane, are stabilized by π-π, δ+-π and/or cation-π interactions according to whether the His is neutral or protonated and the partners are in stacked or T-shape conformations. Here we attempt to probe the relative strength of these interactions as a function of the geometry and protonation state, in gas phase, in water and protein-like environments (acetone, THF and CCl4), by means of quantum chemistry calculations performed up to second order of the Møller-Plesset pertubation theory. Two sets of conformations are considered for that purpose. The first set contains 89 interactions between His and Phe, Tyr, Trp, or Ade, observed in X-ray structures of proteins and protein-ligand complexes. The second set contains model structures obtained by moving an imidazolium/imida-zole moiety above a benzene ring or an adenine moiety. We found that the protonated complexes are much more stable than the neutral ones in gas phase. This higher stability is due to the electrostatic contributions, the electron correlation contributions being equally important in the two forms. Thus, π-π and δ+-π interactions present essentially favorable electron correlation energy terms, whereas cation-π interactions feature in addition favorable electrostatic energies. The pro-tonated complexes remain more stable than the neutral ones in protein-like environments, but the difference is drastically reduced. Furthermore, the T-shape conformation is undoubtedly more favorable than the stacked one in gas phase. This advantage decreases in the solvents, and the stacked conformation becomes even slightly more favorable in water. The frequent occurrence of His-aromatic interactions in catalytic sites, at protein-DNA or protein-ligand interfaces and in 3D domain swapping proteins emphasize their importance in biological processes. © 2005 American Chemical Society.
BibTeX:
@article{CauetRoomanWintjensEtAl2005,
  author = {Cauët, E. and Rooman, M. and Wintjens, R. and Liévin, J. and Biot, C.},
  title = {Histidine-aromatic interactions in proteins and protein-ligand complexes: Quantum chemical study of X-ray and model structures},
  journal = {Journal of Chemical Theory and Computation},
  year = {2005},
  volume = {1},
  pages = {472-483},
  doi = {10.1021/ct049875k}
}
Abstract: Vertical ionization potentials (IPs) of nucleobases embedded in a fully solvated DNA fragment (12-mer B-DNA fragment + 22 sodium counterions + 5760 water molecules equilibrated to 298 K) have been calculated using a combined quantum mechanical molecular mechanics (QM/MM) approach. Calculations of the vertical IP of the anion Cl- are reported that support the accuracy of the application of a QM/MM method to this problem. It is shown that the π nucleotide HOMO origin for the emitted electron is localized on the base by the hydration structure surrounding the DNA in a way similar to that recently observed for pyrimidine nucleotides in aqueous solutions (Slavícě k, P.; et al. J. Am. Chem. Soc. 2009, 131, 6460). In a first step, a high level of theory, CCSD(T)/aug-cc-pVDZ, was used to calculate the vertical IP of each of the four single bases isolated in the QM region while the remaining DNA fragment, counterions, and water solvent molecules were included in the MM region. The calculated vertical IPs show a large positive shift of 3.2-3.3 eV compared to the corresponding gas-phase values. This shift is similar for all four DNA bases. The origin of the large increase in vertical IPs of nucleobases is found to be the long-range electrostatic interactions with the solvation structure outside the DNA helix. Thermal fluctuations in the fluid can result in IP changes of roughly 1 eV on a picosecond time scale. IPs of π-stacked and H-bonded clusters of DNA bases were also calculated using the same QM/MM model but with a lower level of theory, B3LYP/6-31G(d=0.2). An IP shift of 4.02 eV relative to the gas phase is found for a four-base-pair B-DNA duplex configuration. The primary goal of this work was to estimate the influence of long-range solvation interactions on the ionization properties of DNA bases rather than provide highly precise IP evaluations. The QM/MM model presented in this work provides an attractive method to treat the difficult problem of incorporating a detailed long-range structural model of physiological conditions into investigations of the electronic processes in DNA. © 2010 American Chemical Society.
BibTeX:
@article{CauetValievWeare2010,
  author = {Cauët, E. and Valiev, M. and Weare, J.H.},
  title = {Vertical ionization potentials of nucleobases in a fully solvated DNA environment},
  journal = {Journal of Physical Chemistry B},
  year = {2010},
  volume = {114},
  pages = {5886-5894},
  doi = {10.1021/jp9120723}
}
Abstract: Ionization and charge migration in DNA play crucial roles in mechanisms of DNA damage caused by ionizing radiation, oxidizing agents and photo-irradiation. Therefore, an evaluation of the ionization properties of the DNA bases is central to the full interpretation and understanding of the elementary reactive processes that occur at the molecular level during the initial exposure and afterwards. Ab initio quantum mechanical (QM) methods have been successful in providing highly accurate evaluations of key parameters, such as ionization energies (IE) of DNA bases. Hence, in this study, we performed high-level QM calculations to characterize the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration between DNA bases. In particular, we examined the IEs of guanine, the most easily oxidized base, isolated and embedded in base clusters, and investigated the mechanism of charge migration over two and three stacked guanines. The IE of guanine in the human telomere sequence has also been evaluated. We report a simple molecular orbital analysis to explain how modifications in the base sequence are expected to change the efficiency of the sequence as a hole trap. Finally, the application of a hybrid approach combining quantum mechanics with molecular mechanics brings an interesting discussion as to how the native aqueous DNA environment affects the IE threshold of nucleobases.
BibTeX:
@conference{CauetValievWeareEtAl2012,
  author = {Cauët, E. and Valiev, M. and Weare, J.H. and Liévin, J.},
  title = {Quantum mechanical calculations related to ionization and charge transfer in DNA},
  journal = {Journal of Physics: Conference Series},
  year = {2012},
  volume = {373},
  article number = {012003},
  doi = {10.1088/1742-6596/373/1/012003}
}
Abstract: We investigate possible mutations in the genetic code induced by cisplatin with an approach combining molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. Specifically, the impact of platination on the natural tautomeric equilibrium in guanine-cytosine (GC) base pairs is assessed to disclose the possible role played by non-canonical forms in anti-tumour activity. To obtain valuable predictions, the main interactions present in a real DNA environment, namely hydration and stacking, are simultaneously taken into account. According to our results, the Pt-DNA adduct promotes a single proton transfer reaction in GC in the DNA sequence AGGC. Such rare tautomers might play an important role in the cisplatin biological activity since they meet the stability requirements necessary to promote a permanent mutation. This journal is © the Owner Societies 2012.
BibTeX:
@article{Ceron-CarrascoJacqueminCauet2012,
  author = {Cerón-Carrasco, J.P. and Jacquemin, D. and Cauët, E.},
  title = {Cisplatin cytotoxicity: A theoretical study of induced mutations},
  journal = {Physical Chemistry Chemical Physics},
  year = {2012},
  volume = {14},
  pages = {12457-12464},
  doi = {10.1039/c2cp40515f}
}
Abstract: We present here a 2D model of photochemistry for computing the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines at 577.7, 630, and 636.4 nm, in case of the comet 1P/Halley. The presence of O2 within cometary atmospheres, measured by the in situ Rosetta and Giotto missions, necessitates a revision of the usual photochemical models. Indeed, the photodissociation of molecular oxygen also leads to a significant production of oxygen in excited electronic states. In order to correctly model the solar ultraviolet (UV) flux absorption, we consider here a 2D configuration. While the green to red-doublet ratio is not affected by the solar UV flux absorption, estimates of the red-doublet and green lines emissions are, however, overestimated by a factor of 2 in the 1D model compared to the 2D model. Considering a spherical symmetry, emission maps can be deduced from the 2D model in order to be directly compared to ground and/or in situ observations. © 2017 The Authors.
BibTeX:
@article{CessateurDeKeyserMaggioloEtAl2016,
  author = {Cessateur, G. and De Keyser, J. and Maggiolo, R. and Rubin, M. and Gronoff, G. and Gibbons, A. and Jehin, E. and Dhooghe, F. and Gunell, H. and Vaeck, N. and Loreau, J.},
  title = {2D photochemical model for forbidden oxygen line emission for comet 1P/Halley},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {2016},
  volume = {462},
  pages = {S116-S123},
  doi = {10.1093/mnras/stw2150}
}
Abstract: Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water 3.80 ± 0.85 within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P, with a relative error of about 25%. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. Indeed, there is no compelling reason why O2 would not be a common cometary volatile, making revision of earlier assessments regarding the CO2 abundance in cometary atmospheres necessary. The large uncertainties of the CO2 photodissociation cross section imply that more studies are required in order to better constrain the O(1S) and O(1D) production through this mechanism. Space weather phenomena, such as powerful solar flares, could be used as tools for doing so, providing additional information on a good estimation of the O2 abundance within cometary atmospheres. ©2016. The Authors.
BibTeX:
@article{CessateurKeyserMaggioloEtAl2016,
  author = {Cessateur, G. and Keyser, J.D. and Maggiolo, R. and Gibbons, A. and Gronoff, G. and Gunell, H. and Dhooghe, F. and Loreau, J. and Vaeck, N. and Altwegg, K. and Bieler, A. and Briois, C. and Calmonte, U. and Combi, M.R. and Fiethe, B. and Fuselier, S.A. and Gombosi, T.I. and Hässig, M. and Le Roy, L. and Neefs, E. and Rubin, M. and Sémon, T.},
  title = {Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko},
  journal = {Journal of Geophysical Research A: Space Physics},
  year = {2016},
  volume = {121},
  pages = {804-816},
  doi = {10.1002/2015JA022013}
}
Abstract: Direct determination of the radiative forcing of trace gases will be made possible by use of the next generation of nadir-looking spaceborne instruments that provide measurements of atmospheric radiances in the infrared spectral range with improved spectral and spatial resolution. An inversion statistical method has thus been developed and applied to the direct determination of the radiative forcing of methane, based on such instruments as the Fourier-transform Interferometric Monitor for Greenhouse Gases launched onboard the Japanese Advanced Earth Observing Satellite in 1996 and the Infrared Atmospheric Sounding Interferometer planned for the European polar platform Meteorological Operational Satellite in 2000. The method is based on simple statistical laws that directly relate the measured radiances to the radiative forcing by use of an a priori selection of appropriate spectral intervals and global modeling of methane spatial variations. This procedure avoids the use of an indirect determination based on an inversion process that requires precise knowledge of the methane vertical profiles throughout the troposphere. The overall accuracy and precision of this new algorithm are studied, and interfering gases and instrumental characteristics are taken into account. It is shown that radiative forcing can be determined at high horizontal spatial resolution with a precision better than 7% in cloud-free conditions and with well-known surface properties. © 1998 Optical Society of America.
BibTeX:
@article{ChazetteClerbauxMegie1998,
  author = {Chazette, P. and Clerbaux, C. and Mégie, G.},
  title = {Direct estimate of methane radiative forcing by use of nadir spectral radiances},
  journal = {Applied Optics},
  year = {1998},
  volume = {37},
  pages = {3113-3120},
  doi = {10.1364/AO.37.003113}
}
Abstract: Satellite instruments specifically designed to monitor atmospheric carbon dioxide concentrations have not been flown to date but, high-resolution infrared sounders, being launched in the next few years, may offer the possibility of at least a basic carbon dioxide monitoring capability. This paper explores the sensitivity of this new generation of advanced infrared sounders to changing carbon dioxide concentrations and also compares this with uncertainties due to the atmospheric temperature, water vapor, and minor constituent concentrations using the current background errors in numerical weather prediction models as a baseline. The sensitivity results shown are computed for the Infrared Atmospheric Sounding Interferometer (IASI), which is due to fly on the European METOP platform from 2005. We show that although the carbon dioxide signal is below or at the instrument noise for IASI and that uncertainties in temperature and water vapor errors can dominate, a careful averaging of the retrieved carbon dioxide fields over areas of 500 × 500 km2 and 2 weeks should be able to extract changes at the level of 1% or less in the total column carbon dioxide amount. We also show results of an information content study for the Atmospheric InfraRed Sounder, AIRS, data, which suggests 50 channels are adequate for inferring the tropospheric carbon dioxide amounts but that they are not sensitive to CO2 changes in the boundary layer.
BibTeX:
@article{ChedinSaundersHollingsworthEtAl2003,
  author = {Chédin, A. and Saunders, R. and Hollingsworth, A. and Scott, N. and Matricardi, M. and Etcheto, J. and Clerbaux, C. and Armante, R. and Crevoisier, C.},
  title = {The feasibility of monitoring CO2 from high-resoluion infrared sounders},
  journal = {Journal of Geophysical Research D: Atmospheres},
  year = {2003},
  volume = {108},
  pages = {ACH 6-1 ACH 6-19}
}
Abstract: A study based on the INDO method has been made of a variety of σ radicals. The desirability of minimizing the energy with respect to molecular geometry for a number of small radicals (e.g., ·CONH2, H2C=N ·, H2C= ĊH) is discussed. INDO calculations have also been performed for a series of iminoxy radicals (R2C=NO·), the appropriate geometry around the radical center being chosen as that which minimizes the energy for the smallest radical in the series. An alternative method of determining the proportionality constants for relating esr hyperfine splittings to spin density matrix elements is suggested. Spin density distributions in the space around some of the radicals studied are expressed in the form of spin density contour maps.
BibTeX:
@article{ChiuGilbertSutcliffe1972,
  author = {Chiu, M.F. and Gilbert, B.C. and Sutcliffe, B.T.},
  title = {A Theoretical study of hyperfme coupling constants of some σ radicals based on the INDO method},
  journal = {Journal of Physical Chemistry},
  year = {1972},
  volume = {76},
  pages = {553-564}
}
Abstract: Using a generalised product wave function, an expression is given for the isotropic hyperfine coupling constant at a given atom in an aromatic π-radical. By a consistent scheme of approximation the expression is cast in a form in which the coupling constant at a given atom in the radical can be evaluated from the results of a Hückel calculation, provided that certain integrals are known. A scheme for assigning and relating these integrals is given, coupling constants are calculated for 13C, 14N, 17O and 19F atoms, and the calculations compared with experiment. © 1970 Springer-Verlag.
BibTeX:
@article{ChiuSutcliffe1970,
  author = {Chiu, M.F. and Sutcliffe, B.T.},
  title = {A semi-empirical approach to the estimation of ESR isotropic hyperfine coupling constants in aromatic radicals},
  journal = {Theoretica Chimica Acta},
  year = {1970},
  volume = {16},
  pages = {331-345},
  doi = {10.1007/BF00527081}
}
Abstract: Using an extended cavity diode laser referenced to a femtosecond frequency comb, the P(11) absorption line in the ν 1+ν 3 combination band of the most abundant isotopologue of pure acetylene was studied at temperatures of 296, 240, 200, 175, 165, 160, 155, and 150 K to determine pressure-dependent line shape parameters at these temperatures. The laser emission profile, the instrumental resolution, is a Lorentz function characterized by a half width at half the maximum emission (HWHM) of 8.3×10-6 cm-1 (or 250 kHz) for these measurements. Six collision models were tested in fitting the experimental data: Voigt, speed-dependent Voigt, Rautian-Sobel'man, Galatry, and two Rautian-Galatry hybrid models (with and without speed-dependence). Only the speed-dependent Voigt model was able to fit the data to the experimental noise level at all temperatures and for pressures between 3 and nearly 360 torr. The variations of the speed-dependent Voigt profile line shape parameters with temperature were also characterized, and this model accurately reproduces the observations over their entire range of temperature and pressure. © 2011 Springer-Verlag.
BibTeX:
@article{CichMcRavenLopezEtAl2012,
  author = {Cich, M.J. and McRaven, C.P. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.},
  title = {Temperature-dependent pressure broadened line shape measurements in the ν 1+ν 3 band of acetylene using a diode laser referenced to a frequency comb},
  journal = {Applied Physics B: Lasers and Optics},
  year = {2012},
  volume = {109},
  pages = {373-384},
  doi = {10.1007/s00340-011-4829-0}
}
Abstract: Relating to a conjecture on the decomposability of positive maps in 3 ⊗ 3, we solve the open problem of the existence of (5, 5) and (6, 6) PPT edge states. © 2006 Elsevier B.V. All rights reserved.
BibTeX:
@article{Clarisse2006,
  author = {Clarisse, L.},
  title = {Construction of bound entangled edge states with special ranks},
  journal = {Physics Letters, Section A: General, Atomic and Solid State Physics},
  year = {2006},
  volume = {359},
  pages = {603-607},
  doi = {10.1016/j.physleta.2006.07.045}
}
Abstract: Robustness measures as introduced by Vidal and Tarrach (1999 Robustness of entanglement Phys. Rev. A 59 141-55) quantify the extent to which entangled states remain entangled under mixing. Analogously, we introduce here the Schmidt robustness and the random Schmidt robustness. The latter notion is closely related to the construction of Schmidt balls around the identity. We analyse the situation for pure states and provide nontrivial upper and lower bounds. Upper bounds to the random Schmidt-2 robustness allow us to construct a particularly simple distillability criterion. We present two conjectures, the first one is related to the radius of inner balls around the identity in the convex set of Schmidt number n-states. We also conjecture a class of optimal Schmidt witnesses for pure states. © 2006 IOP Publishing Ltd.
BibTeX:
@article{Clarisse2006a,
  author = {Clarisse, L.},
  title = {On the Schmidt robustness of pure states},
  journal = {Journal of Physics A: Mathematical and General},
  year = {2006},
  volume = {39},
  pages = {4239-4249},
  doi = {10.1088/0305-4470/39/16/010}
}
Abstract: An important open problem in quantum information theory is the question of the existence of NPT bound entanglement. In the past years, little progress has been made, mainly because of the lack of mathematical tools to address the problem, (i) In an attempt to overcome this, we show how the distillability problem can be reformulated as a special instance of the separability problem, for which a large number of tools and techniques are available. (ii) Building up to this we also show how the problem can be formulated as a Schmidt number problem. (iii) A numerical method for detecting distillability is presented and strong evidence is given that all 1-copy undistillable Werner states are also 4-copy undistillable. (iv) The same method is used to estimate the volume of distillable states, and the results suggest that bound entanglement is primarily a phenomenon found in low dimensional quantum systems. (v) Finally, a set of one parameter states is presented which we conjecture to exhibit all forms of distillability. © Rinton Press.
BibTeX:
@article{Clarisse2006b,
  author = {Clarisse, L.},
  title = {The distillability problem revisited},
  journal = {Quantum Information and Computation},
  year = {2006},
  volume = {6},
  pages = {539-560}
}
Abstract: A necessary and sufficient condition for one-distillability is formulated in terms of decomposable positive maps. As an application we provide insight into why all states violating the reduction criterion map are distillable and demonstrate how to construct such maps in a systematic way. We establish a connection between a number of existing results, which leads to an elementary proof for the characterization of distillability in terms of two-positive maps. ©2005 The American Physical Society.
BibTeX:
@article{Clarisse2005,
  author = {Clarisse, L.},
  title = {Characterization of distillability of entanglement in terms of positive maps},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2005},
  volume = {71},
  article number = {032332},
  doi = {10.1103/PhysRevA.71.032332}
}
Abstract: Global ammonia emissions have more than doubled since pre-industrial times, largely owing to agricultural intensification and widespread fertilizer use1. In the atmosphere, ammonia accelerates particulate matter formation, thereby reducing air quality. When deposited in nitrogen-limited ecosystems, ammonia can act as a fertilizer. This can lead to biodiversity reductions in terrestrial ecosystems, and algal blooms in aqueous environments2-8. Despite its ecological significance, there are large uncertainties in the magnitude of ammonia emissions, mainly owing to a paucity of ground-based observations and a virtual absence of atmospheric measurements3,8-11. Here we use infrared spectra, obtained by the IASI/MetOp satellite, to map global ammonia concentrations from space over the course of 2008. We identify several ammonia hotspots in middle-low latitudes across the globe. In general, we find a good qualitative agreement between our satellite measurements and simulations made using a global atmospheric chemistry transport model. However, the satellite data reveal substantially higher concentrations of ammonia north of 30° N, compared with model projections. We conclude that ammonia emissions could have been significantly underestimated in the Northern Hemisphere, and suggest that satellite monitoring of ammonia from space will improve our understanding of the global nitrogen cycle. © 2009 Macmillan Publishers Limited. All rights reserved.
BibTeX:
@article{ClarisseClerbauxDentenerEtAl2009,
  author = {Clarisse, L. and Clerbaux, C. and Dentener, F. and Hurtmans, D. and Coheur, P.-F.},
  title = {Global ammonia distribution derived from infrared satellite observations},
  journal = {Nature Geoscience},
  year = {2009},
  volume = {2},
  pages = {479-483},
  doi = {10.1038/ngeo551}
}
Abstract: In this paper we demonstrate the potential of the infrared Fourier transform spectrometer IASI in analysing volcanic eruptions, using the September 2007 eruption at Jebel at Tair as an illustrative example. Detailed radiative transfer calculations are presented, simulating IASI-like transmittance spectra for a variety of volcanic plumes. We analyse the sensitivity of IASI to SO 2 at different altitudes and demonstrate that IASI is in principle capable of sensing SO2 down to the surface. Using the brightness temperature difference of well chosen SO2 channels as a filter, we are able to track the plume of the Jebel at Tair eruption for 12 days, on a par with state of the art UV sounders. A method is presented for quickly estimating the altitude of a volcanic plume based on the relative intensities of the SO2 absorption lines. Despite recent advances, it is still very challenging to retrieve vertical profiles of SO2 from nadir viewing satellites. Currently the most accurate profiles in nadir are retrieved using backtracking of the plume with atmospheric transport models. Via full inverse retrievals using the optimal estimation method, we show the possibility of extracting medium coarse vertical profiles from IASI data. The retrieval allows us to present an evolution of the total mass of SO2 in the plume for the Jebel at Tair eruption. An analytical relation is derived between brightness temperature differences and concentrations, which fits the experimental data very well. The spectral range of IASI also allows retrieval of volcanic aerosols. In the initial plume of the Jebel at Tair eruption, volcanic aerosols were found in the form of ice particles, for which we derived particle sizes. © Author(s) 2008.
BibTeX:
@article{ClarisseCoheurPrataEtAl2008,
  author = {Clarisse, L. and Coheur, P.F. and Prata, A.J. and Hurtmans, D. and Razavi, A. and Phulpin, T. and Hadji-Lazaro, J. and Clerbaux, C.},
  title = {Tracking and quantifying volcanic SO2 with IASI, the September 2007 eruption at Jebel at Tair},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {7723-7734},
  doi = {10.5194/acp-8-7723-2008}
}
Abstract: Hydrogen sulphide (H2S) is one of the main trace gases released from volcanoes with yearly global emissions estimated between 1 and 37 Tg. With sulfur dioxide (SO2, 15-21 Tg/year), it dominates the volcanic sulfur budget, and the emission ratio H2S:SO2 is an important geochemical probe for studying source conditions, sulfur chemistry and magma-water interactions. Contrary to SO2, measurements of H 2S are sparse and difficult. Here we report the first measurements of a large H2S plume from space. Observations were made with the infrared sounder IASI of the volcanic plume released after the 7-8 August 2008 eruption of Kasatochi volcano. The eruption was characterized by 5 consecutive explosive events. The first events were phreatomagmatic producing a plume rich in water vapor and poor in ash and SO2. We show that the observed H2S plume, calculated at 29±10 kT with integrated columns exceeding 140±25 Dobson Units (DU), is likely associated with these first explosions. H2S:SO2 ratios with maximum values of 12±2 are found, representative of redox conditions in the hydrothermal envelop. With a detection threshold of 25 DU, future space observations of H2S plumes are certain. These will be important for improving the atmospheric sulfur budget and characterizing the H2S:SO2 fingerprint of different eruptions. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{ClarisseCoheurChefdevilleEtAl2011,
  author = {Clarisse, L. and Coheur, P.-F. and Chefdeville, S. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C.},
  title = {Infrared satellite observations of hydrogen sulfide in the volcanic plume of the August 2008 Kasatochi eruption},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10804},
  doi = {10.1029/2011GL047402}
}
Abstract: Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI) and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere. © 2013 Author(s).
BibTeX:
@article{ClarisseCoheurPrataEtAl2013,
  author = {Clarisse, L. and Coheur, P.-F. and Prata, F. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C.},
  title = {A unified approach to infrared aerosol remote sensing and type specification},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {2195-2221},
  doi = {10.5194/acp-13-2195-2013}
}
Abstract: In the wake of the June 2011 Nabro eruption, large stratospheric plumes were observed by several instruments up to altitudes of 21 km, much higher than initial reported injection heights. It has been debated whether deep convection associated with the Asian Summer Monsoon anticyclone played a vital role in the vertical transport of the plume. Here we present a new and fast SO2 height retrieval algorithm for observations of the Infrared Atmospheric Sounding Interferometer (IASI). A comprehensive validation with forward trajectories and coincident CALIOP measurements is presented which indicates an accuracy better than 2 km for plumes below 20 km and SO2 columns up to the 1 DU level. We use this new product to analyse the Nabro eruption. Our findings indicate an initial plume located mainly between 15 and 17 km for which the lower parts underwent in succession rapid descent and uplift, within the Asian Monsoon anticyclone circulation, up to the stable thermal tropopause between 16 and 18 km, from where it slowly ascended further into the stratosphere. Evidence is presented that emissions in the first week of the eruption also contributed to the stratospheric sulfur input. This includes a second eruption between 15 and 17 km on the 16th and continuous emissions in the mid-troposphere of which some were also entrained and lifted within the anticyclonic circulation. © 2014 Author(s).
BibTeX:
@article{ClarisseCoheurTheysEtAl2014,
  author = {Clarisse, L. and Coheur, P.-F. and Theys, N. and Hurtmans, D. and Clerbaux, C.},
  title = {The 2011 Nabro eruption, a SO2 plume height analysis using IASI measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {3095-3111},
  doi = {10.5194/acp-14-3095-2014}
}
Abstract: Using 3 years worth of IASI (the Infrared Atmospheric Sounder Interferometer aboard METOP-A) measurements, we have identified 24 major events of uplift and transport of anthropogenic sulfur dioxide. These were all first observed over East Asia, and could be traced for over 60 hours. On 7 November 2010 a sulfur dioxide plume was observed over Northeast China and tracked for five days to North America. We discuss this event in detail with respect to build up; uplift and in-plume chemistry. We found a host of trace gas enhancements in the plume (SO2, CO, PAN, CH3OH, HCOOH and C2H2). A reasonable to very good agreement was found with MOZART-4 modeled ambient columns for all species except methanol, which was underestimated by the model by an order of magnitude. We calculate correlations of the different species and give observational evidence of secondary in-plume formation of methanol and PAN. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{ClarisseFrommNgadiEtAl2011,
  author = {Clarisse, L. and Fromm, M. and Ngadi, Y. and Emmons, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L19806},
  doi = {10.1029/2011GL048976}
}
Abstract: We define the disentangling power of a unitary operator in a similar way as the entangling power defined by Zanardi et al. [P. Zanardi, C. Zalka, L. Faoro, Phys. Rev. A 62 (2000) 030301(R), quant-ph/0005031]. A general formula is derived and it is shown that both quantities are directly proportional. All results concerning the entangling power can simply be translated into similar statements for the disentangling power. In particular, the disentangling power is maximal for certain permutations derived from orthogonal Latin squares. These permutations can therefore be interpreted as those that distort entanglement in a maximal way. © 2007 Elsevier B.V. All rights reserved.
BibTeX:
@article{ClarisseGhoshSeveriniEtAl2007,
  author = {Clarisse, L. and Ghosh, S. and Severini, S. and Sudbery, A.},
  title = {The disentangling power of unitaries},
  journal = {Physics Letters, Section A: General, Atomic and Solid State Physics},
  year = {2007},
  volume = {365},
  pages = {400-402},
  doi = {10.1016/j.physleta.2007.02.001}
}
Abstract: The notion of entangling power of unitary matrices was introduced by Zanardi, [Phys. Rev. A 62, 030301 (2000)]. We study the entangling power of permutations, given in terms of a combinatorial formula. We show that the permutation matrices with zero entangling power are, up to local unitaries, the identity and the swap. We construct the permutations with the minimum nonzero entangling power for every dimension. With the use of orthogonal latin squares, we construct the permutations with the maximum entangling power for every dimension. Moreover, we show that the value obtained is maximum over all unitaries of the same dimension, with a possible exception for 36. Our result enables us to construct generic examples of 4-qudit maximally entangled states for all dimensions except for 2 and 6. We numerically classify, according to their entangling power, the permutation matrices of dimensions 4 and 9, and we give some estimates for higher dimensions. © 2005 The American Physical Society.
BibTeX:
@article{ClarisseGhoshSeveriniEtAl2005,
  author = {Clarisse, L. and Ghosh, S. and Severini, S. and Sudbery, A.},
  title = {Entangling power of permutations},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2005},
  volume = {72},
  article number = {012314},
  doi = {10.1103/PhysRevA.72.012314}
}
Abstract: Thermal infrared sounding of sulphur dioxide (SO 2) from space has gained appreciation as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO 2 in the infrared, and atmospheric sounders, such as AIRS (Atmospheric Infrared Sounder), TES (Tropospheric Emission Spectrometer) and IASI (Infrared Atmospheric Sounding Interferometer) have the ability to globally monitor SO 2 abundances. Most of the observed SO 2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO 2 above ∼5 km altitude using high resolution infrared sounders and apply it to measurements of IASI. The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3-5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro. © 2012 Author(s). CC Attribution 3.0 License.
BibTeX:
@article{ClarisseHurtmansClerbauxEtAl2012,
  author = {Clarisse, L. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Ngadi, Y. and Coheur, P.-F.},
  title = {Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {581-594},
  doi = {10.5194/amt-5-581-2012}
}
Abstract: We present a sophisticated radiative transfer code for modeling outgoing IR radiation from planetary atmospheres and, conversely, for retrieving atmospheric properties from high-resolution nadir-observed spectra. The forward model is built around a doubling-adding routine and calculates, in a spherical refractive geometry, the outgoing radiation emitted by the Earth and the atmosphere containing one layer of aerosol. The inverse model uses an optimal estimation approach and can simultaneously retrieve atmospheric trace gases, aerosol effective radius, and concentration. It is different from existing codes, as most forward codes dealing with multiple scattering assume a plane-parallel atmosphere, and as for the retrieval, it does not rely on precalculated spectra, the use of microwindows, or two-step retrievals. The simultaneous retrieval on a broad spectral range exploits the full potential of current state-of-the-art hyperspectral IR sounders, such as AIRS and IASI, and should be particularly useful in studying major pollution events. We present five example retrievals of IASI spectra observed in the range from 800 to 1200 cm-1 above dust, volcanic ash, sulfuric acid, ice particles, and biomass burning aerosols. © 2010 Optical Society of America.
BibTeX:
@article{ClarisseHurtmansPrataEtAl2010,
  author = {Clarisse, L. and Hurtmans, D. and Prata, A.J. and Karagulian, F. and Clerbaux, C. and De Mazière, M. and Coheur, P.-F.},
  title = {Retrieving radius, concentration, optical depth, and mass of different types of aerosols from high-resolution infrared nadir spectra},
  journal = {Applied Optics},
  year = {2010},
  volume = {49},
  pages = {3713-3722},
  doi = {10.1364/AO.49.003713}
}
Abstract: In the first part of this chapter, the spectral content of the thermal infrared spectral region for the sounding of volcanic eruptions is explored through analysis of simulated and real observed spectra. Next, we review the literature on algorithms for the identification and retrieval of volcanic ash, both from broadband and hyperspectral infrared measurements. The final part of this chapter treats the topic of validation of satellite-based ash retrievals. © 2016 Elsevier Ltd. All rights reserved.
BibTeX:
@book{ClarissePrata2016,
  author = {Clarisse, L. and Prata, F.},
  title = {Infrared Sounding of Volcanic Ash},
  journal = {Volcanic Ash: Hazard Observation},
  year = {2016},
  pages = {189-215},
  doi = {10.1016/B978-0-08-100405-0.00017-3}
}
Abstract: Remote satellite detection of airborne volcanic ash is important for mitigating hazards to aviation and for calculating plume altitudes. Infrared sounders are essential for detecting ash, as they can distinguishing aerosol type and can be used day and night. While broadband sensors are mainly used for this purpose, they have inherent limitations. Typically, water and ice can mask volcanic ash, while wind blown dust can yield false detection. High spectral resolution sounders should be able to overcome some of these limitations. However, existing detection methods are not easily applicable to hyperspectral sounders and there is therefore a pressing need for novel techniques. In response, we propose a sensitive and robust volcanic ash detection method for hyperspectral sounders based on correlation coefficients and demonstrate it on IASI observations. We show that the method differentiates ash from clouds and dust. Easy to implement, it could contribute to operational volcanic hazard mitigation. © 2010 by the American Geophysical Union.
BibTeX:
@article{ClarissePrataLacourEtAl2010,
  author = {Clarisse, L. and Prata, F. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {A correlation method for volcanic ash detection using hyperspectral infrared measurements},
  journal = {Geophysical Research Letters},
  year = {2010},
  volume = {37},
  article number = {L19806},
  doi = {10.1029/2010GL044828}
}
Abstract: [1] Thermal infrared nadir sounders are ideal for observing total columns or vertical profiles of atmospheric gases such as water, carbon dioxide and ozone. High resolution sounders with a spectral resolution below 5 cm -1 can distinguish fine spectral features of trace gases. Forty years after the launch of the first hyperspectral sounder IRIS, we have now several state of the art instruments in orbit, with improved instrumental specifications. In this letter we give an overview of the trace gases which have been observed by infrared nadir sounders, focusing on new observations of the Infrared Atmospheric Sounding Interferometer (IASI). We present typical observations of 14 rare reactive trace gas species. Several species are reported here for the first time in nadir view, including nitrous acid, furan, acetylene, propylene, acetic acid, formaldehyde and hydrogen cyanide, observations which were made in a pyrocumulus cloud from the Australian bush fires of February 2009. Being able to observe this large number of reactive trace gases will likely improve our knowledge of source emissions and their impact on the environment and climate.
BibTeX:
@article{ClarisseRHoniCoheurEtAl2011,
  author = {Clarisse, L. and R'Honi, Y. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Thermal infrared nadir observations of 24 atmospheric gases},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10802},
  doi = {10.1029/2011GL047271}
}
Abstract: [1] Atmospheric ammonia (NH3) has recently been observed with infrared sounders from space. Here we present 1 year of detailed bidaily satellite retrievals with the Infrared Atmospheric Sounding Interferometer and some retrievals of the Tropospheric Emission Spectrometer over the San Joaquin Valley, California, a highly polluted agricultural production region. Several sensitivity issues are discussed related to the sounding of ammonia, in terms of degrees of freedom, averaging kernels, and altitude of maximum sensitivity and in relation to thermal contrast and concentration. We also discuss their seasonal dependence and sources of errors. We demonstrate boundary layer sensitivity of infrared sounders when there is a large thermal contrast between the surface and the bottom of the atmosphere. For the San Joaquin Valley, large thermal contrast is the case for daytime measurements in spring, summer, and autumn and for nighttime measurements in autumn and winter when a large negative thermal contrast is amplified by temperature inversion. © 2010 by the American Geophysical Union.
BibTeX:
@article{ClarisseShephardDentenerEtAl2010,
  author = {Clarisse, L. and Shephard, M.W. and Dentener, F. and Hurtmans, D. and Cady-Pereira, K. and Karagulian, F. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Satellite monitoring of ammonia: A case study of the San Joaquin Valley},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D13302},
  doi = {10.1029/2009JD013291}
}
Abstract: Recently, P. Wocjan and M. Horodecki [Open Syst. Inf. Dyn. 12, 331 (2005)] gave a characterization of combinatorially independent permutation separability criteria. Combinatorial independence is a necessary condition for permutations to yield truly independent criteria meaning that no criterion is strictly stronger that any other. In this paper we observe that some of these criteria are still dependent and analyze why these dependencies occur. To remove them we introduce an improved necessary condition and give a complete classification of the remaining permutations. We conjecture that the remaining class of criteria only contains truly independent permutation separability criteria. Our conjecture is based on the proof that for two, three and four parties all these criteria are truly independent and on numerical verification of their independence for up to 8 parties. It was commonly believed that for three parties there were 9 independent criteria, here we prove that there are exactly 6 independent criteria for three parties and 22 for four parties. © Rinton Press.
BibTeX:
@article{ClarisseWocjan2006,
  author = {Clarisse, L. and Wocjan, P.},
  title = {On independent permutation separability criteria},
  journal = {Quantum Information and Computation},
  year = {2006},
  volume = {6},
  pages = {277-288}
}
Abstract: Collision effects on water vapor at low concentration in mixture with noble gases and nitrogen have been studied by Fourier transform spectroscopy in a pressure range where line narrowing by dynamic confinement (Dicke effect) and collision broadening are observable, i.e. when the Voigt function cannot reproduce the observed profiles. Precise values of the broadening parameter have been obtained for R branch lines of the ν2 band of H2O and narrowing parameter values were derived using the soft and hard collision models. Furthermore, it is shown that, when neglecting the confinement effect, systematic errors on the broadening parameters may be introduced and reach several percents for the narrowest lines corresponding to the highest J values. © 2000 Elsevier Science Ltd. All rights reserved.
BibTeX:
@article{ClaveauHenryHurtmansEtAl2001,
  author = {Claveau, C. and Henry, A. and Hurtmans, D. and Valentin, A.},
  title = {Narrowing and broadening parameters of H2O lines perturbed by He, Ne, Ar, Kr and nitrogen in the spectral range 1850-2140 cm-1},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2001},
  volume = {68},
  pages = {273-298},
  doi = {10.1016/S0022-4073(00)00025-X}
}
Abstract: Collision effects on water vapor line profiles perturbed by nitrogen at room temperature have been studied by Fourier transform and tunable diode laser spectroscopy. Narrowing effect due to molecular confinement (Dicke effect) has been observed for P and Q branch lines of the v2 band of H2O with Fourier transform spectrometer. Narrowing and broadening parameters have been determined using the soft and hard collision models. A more precise study on three R-branch lines with a frequency stabilized diode laser spectrometer allows to perform the comparison between the two collision models at low pressure and to analyze the different narrowing effects when the pressure increases taking into account the molecular confinement and the absorber speed dependent effects. © 2002 Elsevier Science (USA).
BibTeX:
@article{ClaveauHenryLepereEtAl2002,
  author = {Claveau, C. and Henry, A. and Lepère, M. and Valentin, A. and Hurtmans, D.},
  title = {Narrowing and broadening parameters for H2O lines in the v2 band perturbed by nitrogen from fourier transform and tunable diode laser spectroscopy},
  journal = {Journal of Molecular Spectroscopy},
  year = {2002},
  volume = {212},
  article number = {98539},
  pages = {171-185},
  doi = {10.1006/jmsp.2002.8539}
}
Abstract: In order to study absorption line profiles using the stabilized diode laser spectrometer of Laboratoire de Physique Moléculaire et Applications (LPMA), a reliable determination of the emission line shape of different diodes laser is needed. In the near infrared region (1.39 and 1.66 μm) we used Distributed Feed Back diode lasers which operate around room temperature and in the middle infrared (5 and 8 μm) we used lead salt diode lasers cooled in a helium closed cycle cryostat or in a liquid nitrogen dewar. Some results obtained in H2O line profile studies in the 1.39 and 5 μm regions are presented as examples demonstrating how absorption line profile measurements can lead to erroneous values of the spectroscopic parameters when the contribution of the diode laser emission line width is neglected. © 2002 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{ClaveauLepereDufourEtAl2002,
  author = {Claveau, C. and Lepère, M. and Dufour, G. and Valentin, A. and Henry, A. and Camy-Peyret, C. and Hurtmans, D.},
  title = {Diode laser emission linewidth determination: Application to H2O line profile studies in the 5 and 1.4 μm regions},
  journal = {Spectrochimica Acta - Part A Molecular and Biomolecular Spectroscopy},
  year = {2002},
  volume = {58},
  article number = {3454},
  pages = {2313-2321},
  doi = {10.1016/S1386-1425(02)00046-X}
}
Abstract: Infrared spectra of 16O12C17O, 17O12C17O, and 17O12C18O in a carbon dioxide sample enriched with oxygen-17 have been recorded with a resolution of about 0.0025 cm-1 in the regions of the fundamental bands, v2 (600-800 cm-1) and v3 (2200-2400 cm-1), and in the region of the "forbidden" band, v1 (1200-1400 cm-1), using the long path difference Fourier transform spectrometer of the LPMA in Paris. For each species, the first hot band in the 4.5-μm region and two hot bands at least in the 15-μm region have been studied for the first time, and a simultaneous reduction of wavenumbers measured in different spectral regions has been carried out yielding new or improved spectroscopic constants. Line intensities have been measured in the region of the v2 and v3 bands of 16O12C17O, and the corresponding rotationless transition dipole moments and Herman-Wallis coefficients have been reported. © 1998 Academic Press.
BibTeX:
@article{ClaveauTeffoHurtmansEtAl1998,
  author = {Claveau, C. and Teffo, J.-L. and Hurtmans, D. and Valentin, A.},
  title = {Infrared fundamental and first hot bands of O12C17O isotopic variants of carbon dioxide},
  journal = {Journal of Molecular Spectroscopy},
  year = {1998},
  volume = {189},
  pages = {153-195},
  doi = {10.1006/jmsp.1998.7546}
}
Abstract: Infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded with a resolution of about 0.0025 cm-1 in the region of the laser bands near 10 and 9 μm, using the long path difference Fourier Transform Spectrometer of the LPMA in Paris. The two laser bands of the 16O12C17O and 17O12C18O species have been analyzed for the first time. Line intensities for several isotopic species have been measured in this region and the rotationless transition dipole moments and Herman-Wallis coefficients of the corresponding bands have been reported. In particular intensities, alternation in the spectra of 17O12C17O has been analyzed. © 1999 Academic Press.
BibTeX:
@article{ClaveauTeffoHurtmansEtAl1999,
  author = {Claveau, C. and Teffo, J.-L. and Hurtmans, D. and Valentin, A. and Gamache, R.R.},
  title = {Line positions and absolute intensities in the laser bands of carbon-12 oxygen-17 isotopic species of carbon dioxide},
  journal = {Journal of Molecular Spectroscopy},
  year = {1999},
  volume = {193},
  pages = {15-32},
  doi = {10.1006/jmsp.1998.7704}
}
Abstract: Atmospheric remote sounding from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. The IASI nadir looking thermal infrared sounder onboard MetOp will provide 15 years of global scale observations for a series of key atmospheric species, with unprecedented spatial sampling and coverage. This paper gives an overview of the instrument's capability for measuring atmospheric composition in the perspective of chemistry and air quality. The assessment is made in terms of species, accuracy and vertical information. Global distributions are presented for CO, CH4, O3 (total and tropospheric), HNO3, NH3, and volcanic SO2. Local distributions of organic species measured during fire events, such as C2H4, CH3OH, HCOOH, and PAN are also shown. For each species or process, the link is made to specialized papers in this issue. © 2009 Author(s).
BibTeX:
@article{ClerbauxBoynardClarisseEtAl2009,
  author = {Clerbaux, C. and Boynard, A. and Clarisse, L. and George, M. and Hadji-Lazaro, J. and Herbin, H. and Hurtmans, D. and Pommier, M. and Razavi, A. and Turquety, S. and Wespes, C. and Coheur, P.-F.},
  title = {Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6041-6054},
  doi = {10.5194/acp-9-6041-2009}
}
Abstract: Within the next 5 years, several instruments launched on polar orbiting satellites will provide high-resolution infrared remote-sensing measurements of CO, CH4, and O3 on a global scale. The upwelling spectral radiances to be recorded by a nadir-looking remote sensor have been simulated using a high-resolution radiative code (line-by-line radiative transfer model (LBLRTM)) coupled to a three-dimensional chemical transport model (intermediate model of the annual and global evolution of species (IMAGES)). The instrumental specifications of the Fourier transform interferometric monitor for greenhouse gases/Advanced Earth Observing System (IMG/ADEOS) and infrared atmospheric sounding interferometer ( IASI/METOP) were used to generate realistic data. Calculations have been performed to assess the sensitivity of the nadir spectral radiances to changes in the gas concentration, temperature profile and to instrumental characteristics. We provide spectral intervals for an efficient retrieval of these species, together with a set of climatological tropospheric standard mixing ratio profiles. Copyright 1998 by the American Geophysical Union.
BibTeX:
@article{ClerbauxChazetteHadji-LazaroEtAl1998,
  author = {Clerbaux, C. and Chazette, P. and Hadji-Lazaro, J. and Mégie, G. and Müller, J.-F. and Clough, S.A.},
  title = {Remote sensing of CO, CH4, and O3 using a spaceborne nadir-viewing interferometer},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {1998},
  volume = {103},
  article number = {98JD01422},
  pages = {18999-19013},
  doi = {10.1029/98JD01422}
}
Abstract: Atmospheric spectra to be recorded in the infrared spectral range by a spaceborne Fourier transform spectrometer using a nadir view have been simulated. Relevant spectral domains have been selected for the retrieval of carbon monoxide, methane, ozone and nitrous oxide. A new inversion algorithm using neural networks techniques is proposed to retrieve integrated contents and low resolution vertical profiles.
BibTeX:
@conference{ClerbauxChazetteMegie1995,
  author = {Clerbaux, Cathy and Chazette, Patrick and Megie, Gerard J.},
  title = {Tropospheric concentrations of infrared absorbing molecules using a nadir-looking Fourier transform spectrometer},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {1995},
  volume = {2578},
  pages = {148-153}
}
Abstract: Satellite measurements are now recognized as a key element for the early detection and characterization of volcanic eruptions, in particular in the context of aircraft routing. A common tracer of volcanic plumes is sulfur dioxide (SO2), which so far has been measured by ultraviolet-visible (UV-vis) instruments and multispectral infrared (IR) sounders. Here we report the first SO2 vertical profile retrieved from high spectral resolution thermal infrared nadir radiance spectra and we provide information on both the quantity of gas emitted and its altitude. From the radiance spectra provided by the Tropospheric Emission Spectrometer (TES) aboard the NASA AURA satellite, and owing to the ∼0.1 cm-1 (apodized) spectral resolution, elevated levels of SO2 were measured following volcanic eruptions occurring in 2005 (Manam, Sierra Negra) and 2006 (Rabaul, Nyamuragira). Column values are found to be in good agreement with the data provided by Ozone Mapping Instrument (OMI), a UV-vis instrument also onboard the AURA satellite. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{ClerbauxCoheurClarisseEtAl2008,
  author = {Clerbaux, C. and Coheur, P.-F. and Clarisse, L. and Hadji-Lazaro, J. and Hurtmans, D. and Turquety, S. and Bowman, K. and Worden, H. and Carn, S.A.},
  title = {Measurements of so2 profiles in volcanic plumes from the NASA Tropospheric Emission Spectrometer (TES)},
  journal = {Geophysical Research Letters},
  year = {2008},
  volume = {35},
  article number = {L22807},
  doi = {10.1029/2008GL035566}
}
Abstract: This paper presents a comprehensive analysis of the CO observations acquired during the first eight months (January to September 2004) of the ACE mission. We show that the ACE high-resolution Fourier transform spectrometer (ACE-FTS), which operates in the solar occultation geometry and covers a wide spectral interval in the infrared, provides useful measurements in both the CO 1-0 and 2-0 vibrational bands. Vertically-resolved CO concentration profiles are retrieved, extending from the mid-troposphere to the thermosphere (from about 5 to 110 km). We have analyzed the latitudinal variability of the measurements, from which various physical and chemical atmospheric processes are highlighted for further study. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{ClerbauxCoheurHurtmansEtAl2005,
  author = {Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Barret, B. and Carleer, M. and Colin, R. and Semeniuk, K. and McConnell, J.C. and Boone, C. and Bernath, P.},
  title = {Carbon monoxide distribution from the ACE-FTS solar occultation measurements},
  journal = {Geophysical Research Letters},
  year = {2005},
  volume = {32},
  article number = {L16S01},
  pages = {1-4},
  doi = {10.1029/2005GL022394}
}
Abstract: The B3Σ--X3Σ- transition of the SO radical has been reinvestigated at high resolution for two isotopomers (32SO16O) and 32SO18O rotational analysis of several bands has led to a reassignment of the branches and to a new set of molecular constants for the v′ = 0 and v′ = 1 levels of the B state. A limiting curve of predissociation of the B3Σ- state by a shallow C3Π state has been obtained, which yields a precise value of the dissociation energy of the X3Σ- state: D″e = 43 680 ± 5 cm-1. Many new rotational perturbations were observed in the B3Σ- state, but a complete understanding of these was not possible. © 1994 Academic Press, Inc.
BibTeX:
@article{ClerbauxColin1994,
  author = {Clerbaux, C. and Colin, R.},
  title = {A reinvestigation of the b3Σ--x3Σ- transition of the so radical},
  journal = {Journal of Molecular Spectroscopy},
  year = {1994},
  volume = {165},
  pages = {334-348},
  doi = {10.1006/jmsp.1994.1137}
}
Abstract: The Global Warming Potentials (GWPs) of CH2F‐CHF2 (HFC‐143) have been estimated for different time horizons. Radiative forcings associated with this CFC alternative have been derived relative to CFC‐11 and CO2 by introducing laboratory measured absorption cross sections into a coupled chemical‐radiative model. Copyright 1994 by the American Geophysical Union.
BibTeX:
@article{ClerbauxColin1994a,
  author = {Clerbaux, C. and Colin, R.},
  title = {Determination of the infrared cross sections and global warming potentials of 1,1,2‐trifluoroethane (HFC‐143)},
  journal = {Geophysical Research Letters},
  year = {1994},
  volume = {21},
  pages = {2377-2380},
  doi = {10.1029/94GL02365}
}
Abstract: The absorption and the emission spectra of the BeH and BeD molecules in the region of 1850 Å are rotationally analysed. The features observed are shown to correspond to a transition between thèZ+ ground state and a 3d molecular complex that is strongly predissociated by thè C2Z+ state. Rotational constants for the v = 0 and v = 1 levels of the 3d state are derived by matrix X2Σ+diagonalization techniques, assuming interaction with the F(4pσ)2Σ+state. A tentative assignaient of previously observed absorption bands to transitions involving the v = 2 level of the 3d state is given. The 2-0 band of the B2∏-X2Σ++ transition of BeH and BeD is also identified in this region. The predissociation by the C2Σ+state is discussed. © 1991 Taylor &amp; Francis Ltd.
BibTeX:
@article{ClerbauxColin1991,
  author = {Clerbaux, C. and Colin, R.},
  title = {The 3d rydberg state of the beh molecule},
  journal = {Molecular Physics},
  year = {1991},
  volume = {72},
  pages = {471-486},
  doi = {10.1080/00268979100100361}
}
Abstract: Absorption cross sections have been obtained in the infrared atmospheric window, between 600 and 1500 cm-1, for 10 alternative hydrohalocarbons: HCFC22, HCFC123, HCFC124, HCFC141b, HCFC142b, HCFC225ca, HCFC225cb, HFC125, HFC134a and HFC152a. The measurements were made at three temperatures (287 K, 270 K and 253 K) with a Fourier transform spectrometer operating at 0.03 cm-1 apodized resolution. Integrated cross sections have been introduced into a two-dimensional radiative-chemical-dynamical model in order to calculate the global warming potential (GWP) of each gas. -Authors
BibTeX:
@article{ClerbauxColinSimonEtAl1993,
  author = {Clerbaux, C. and Colin, R. and Simon, P.C. and Granier, C.},
  title = {Infrared cross sections and global warming potentials of 10 alternative hydrohalocarbons},
  journal = {Journal of Geophysical Research},
  year = {1993},
  volume = {98},
  pages = {10,491-10,497}
}
BibTeX:
@article{ClerbauxCrevoisier2013,
  author = {Clerbaux, C. and Crevoisier, C.},
  title = {New Directions: Infrared remote sensing of the troposphere from satellite: Less, but better},
  journal = {Atmospheric Environment},
  year = {2013},
  volume = {72},
  pages = {24-26},
  doi = {10.1016/j.atmosenv.2013.01.057}
}
Abstract: Carbon monoxide (CO) is a key species for tracking pollution plumes. The Measurement Of Pollution in The Troposphere (MOPITT) mission onboard the Terra satellite has already provided 7.5 years of CO atmospheric concentration measurements around the globe. Limited sensitivity to the boundary layer is well known to be a weakness of nadir looking thermal infrared sounders. This paper investigates the possibility of using the MOPITT surface measurements to detect CO emitted by cities and urban centers. By selecting the data and averaging them over long time periods, we demonstrate that the CO pollution arising from the large cities and urban areas can be distinguished from the background transported pollution. The more favorable observations are obtained during daytime and at locations where the thermal contrast (temperature gradient) between the surface and lower atmosphere is significant. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{ClerbauxEdwardsDeeterEtAl2008,
  author = {Clerbaux, C. and Edwards, D.P. and Deeter, M. and Emmons, L. and Lamarque, J.-F. and Tie, X.X. and Massie, S.T. and Gille, J.},
  title = {Carbon monoxide pollution from cities and urban areas observed by the Terra/MOPITT mission},
  journal = {Geophysical Research Letters},
  year = {2008},
  volume = {35},
  article number = {L03817},
  doi = {10.1029/2007GL032300}
}
Abstract: The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), a good tracer of pollution plumes and atmospheric dynamics, is one of the key species provided by the primary instrument, the ACE-Fourier Transform Spectrometer (ACE-FTS). This instrument performs measurements in both the CO 1-0 and 2-0 ro-vibrational bands, from which vertically resolved CO concentration profiles are retrieved, from the mid-troposphere to the thermosphere. This paper presents an updated description of the ACE-FTS version 2.2 CO data product, along with a comprehensive validation of these profiles using available observations (February 2004 to December 2006). We have compared the CO partial columns with ground-based measurements using Fourier transform infrared spectroscopy and millimeter wave radiometry, and the volume mixing ratio profiles with airborne (both high-altitude balloon flight and airplane) observations. CO satellite observations provided by nadir-looking instruments (MOPITT and TES) as well as limb-viewing remote sensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS CO products. We show that the ACE-FTS measurements provide CO profiles with small retrieval errors (better than 5% from the upper troposphere to 40 km, and better than 10% above). These observations agree well with the correlative measurements, considering the rather loose coincidence criteria in some cases. Based on the validation exercise we assess the following uncertainties to the ACE-FTS measurement data: better than 15% in the upper troposphere (8-12 km), than 30% in the lower stratosphere (12-30 km), and than 25% from 30 to 100 km. © Author(s) 2008.
BibTeX:
@article{ClerbauxGeorgeTurquetyEtAl2008,
  author = {Clerbaux, C. and George, M. and Turquety, S. and Walker, K.A. and Barret, B. and Bernath, P. and Boone, C. and Borsdorff, T. and Cammas, J.P. and Catoire, V. and Coffey, M. and Coheur, P.-F. and Deeter, M. and De Mazière, M. and Drummond, J. and Duchatelet, P. and Dupuy, E. and De Zafra, R. and Eddounia, F. and Edwards, D.P. and Emmons, L. and Funke, B. and Gille, J. and Griffith, D.W.T. and Hannigan, J. and Hase, F. and Höpfner, M. and Jones, N. and Kagawa, A. and Kasai, Y. and Kramer, I. and Le Flochmoën, E. and Livesey, N.J. and López-Puertas, M. and Luo, M. and Mahieu, E. and Murtagh, D. and Nédélec, P. and Pazmino, A. and Pumphrey, H. and Ricaud, P. and Rinsland, C.P. and Robert, C. and Schneider, M. and Senten, C. and Stiller, G. and Strandberg, A. and Strong, K. and Sussmann, R. and Thouret, V. and Urban, J. and Wiacek, A.},
  title = {CO measurements from the ACE-FTS satellite instrument: Data analysis and validation using ground-based, airborne and spaceborne observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {2569-2594},
  doi = {10.5194/acp-8-2569-2008}
}
BibTeX:
@article{ClerbauxGilleEdwards2004,
  author = {Clerbaux, C. and Gille, J. and Edwards, D.},
  title = {New Directions: Infrared measurements of atmospheric pollution from space},
  journal = {Atmospheric Environment},
  year = {2004},
  volume = {38},
  pages = {4599-4601},
  doi = {10.1016/j.atmosenv.2004.05.005}
}
Abstract: Carbon monoxide measurements are obtained from the analysis of the spectra provided by the Interferometric Monitor for Greenhouse Gases (IMG) instrument, which flew on board the Japanese ADEOS satellite. The averaging kernel function of the instrument, which provides the sensitivity of retrieved CO to the vertical atmospheric layers, is calculated. A sequential assimilation approach is used to incorporate this CO data set, along with a detailed associated error budget, into a global three-dimensional chemistry-transport model (MOZART version 2). We show how data assimilation allows one to highlight the differences between modeled and observed CO global distribution. Surface CO mixing ratios computed after assimilation of total columns provided by the IMG instrument are compared with the National Oceanic and Atmospheric Administration (NOAA) - Climate Monitoring and Diagnostics Laboratory (CMDL) in situ measurements, and a good agreement is found between the two data sets. Copyright 2001 by the American Geophysical Union.
BibTeX:
@article{ClerbauxHadji-LazaroHauglustaineEtAl2001,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Hauglustaine, D. and Mégie, G. and Khattatov, B. and Lamarque, J.-F.},
  title = {Assimilation of carbon monoxide measured from satellite in a three-dimensional chemistry-transport model},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2001},
  volume = {106},
  article number = {2000JD900682},
  pages = {15385-15394},
  doi = {10.1029/2000JD900682}
}
Abstract: The high-resolution atmospheric spectra recorded by the Interferometric Monitor for Greenhouse gases instrument on the ADvanced Earth Observing System (IMG/ADEOS) in June, 1997, were analyzed by two different and complementary inversion algorithms to retrieve CO total columns. Spectral fits of high quality were obtained using a global fit algorithm on selected cloud-free measurements. Global distribution maps of CO obtained using a fast neural network retrieval algorithm are compared to the results provided by current chemistry-transport models. These studies highlight the need for complementary information (temperature, emissivity, instrumental function, and cloud content) to retrieve accurate CO vertical columns.
BibTeX:
@article{ClerbauxHadji-LazaroPayanEtAl1999a,
  author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Payan, Sebastien and Camy-Peyret, Claude and Megie, Gerard},
  title = {Retrieval of CO columns from IMG/ADEOS spectra},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1999},
  volume = {37},
  pages = {1657-1661},
  doi = {10.1109/36.763283}
}
Abstract: The high-resolution atmospheric spectra recorded by the Interferometric Monitor for Greenhouse gases instrument on the ADvanced Earth Observing System (IMG/ADEOS) in June, 1997, were analyzed by two different and complementary inversion algorithms to retrieve CO total columns. Spectral fits of high quality were obtained using a global fit algorithm on selected cloud-free measurements. Global distribution maps of CO obtained using a fast neural network retrieval algorithm are compared to the results provided by current chemistry-transport models. These studies highlight the need for complementary information (temperature, emissivity, instrumental function, and cloud content) to retrieve accurate CO vertical columns. Index Terms - Atmospheric measurements, infrared spectroscopy, least square method, neural networks. © 1999 IEEE.
BibTeX:
@article{ClerbauxHadji-LazaroPayanEtAl1999,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Payan, S. and Camy-Peyret, C. and Mégie, G.},
  title = {Retrieval of CO Columns from IMG/ADEOS Spectra},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1999},
  volume = {37},
  pages = {1645-1656},
  doi = {10.1109/36.763281}
}
Abstract: Four inversion schemes based on various retrieval approaches (digital gas correlation, nonlinear least squares, global fit adjustment, and neural networks) developed to retrieve CO from nadir radiances measured by such downward-looking satelliteborne instruments as the Measurement of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Infrared Atmospheric Sounding Interferometer (IASI) instruments were compared both for simulated cases and for atmospheric spectra recorded by the Interferometric Monitor for Greenhouse Gases (IMG). The sensitivity of the retrieved CO total column amount to properties that may affect the inversion accuracy (noise, ancillary temperature profile, and water-vapor content) was investigated. The CO column amounts for the simulated radiance spectra agreed within 4%, whereas larger discrepancies were obtained when atmospheric spectra recorded by the IMG instrument were analyzed. The assumed vertical temperature profile is shown to be a critical parameter for accurate CO retrieval. The instrument’s line shape was also identified as a possible cause of disagreement among the results provided by the groups of scientists who are participating in this study. © 2002 Optical Society of America.
BibTeX:
@article{ClerbauxHadji-LazaroPayanEtAl2002,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Payan, S. and Camy-Peyret, C. and Wang, J. and Edwards, D.P. and Luo, M.},
  title = {Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms},
  journal = {Applied Optics},
  year = {2002},
  volume = {41},
  pages = {7068-7078},
  doi = {10.1364/AO.41.007068}
}
Abstract: The IASI mission flying onboard the MetOp satellites has been providing global observations of the air composition twice a day since 2007. From the atmospheric spectra recorded by the instruments in the thermal infrared spectral range, concentrations of a series of trace gases can be monitored, enhanced levels of pollution can be detected, and particle types can be determined to some extent. This paper recalls the historical context for the IASI remote sensor, reviews its capability to observe some key species for global and regional pollution monitoring, and reports on information services that benefit from the mission. © 2015 Academie des sciences
BibTeX:
@article{ClerbauxHadji-LazaroTurquetyEtAl2015,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Boynard, A. and Pommier, M. and Safieddine, S. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Van Damme, M.},
  title = {Tracking pollutants from space: Eight years of IASI satellite observation},
  journal = {Comptes Rendus - Geoscience},
  year = {2015},
  volume = {347},
  pages = {134-144},
  doi = {10.1016/j.crte.2015.06.001}
}
BibTeX:
@article{ClerbauxHadji-LazaroTurquetyEtAl2007,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Coheur, P.-F. and Hurtmans, D. and Wespes, C. and Herbin, H. and Blumstein, D. and Tourniers, B. and Phulpin, T.},
  title = {The IASI/MetOp1Mission: First observations and highlights of its potential contribution to GMES2},
  journal = {Space Research Today},
  year = {2007},
  volume = {168},
  pages = {19-24},
  doi = {10.1016/S0045-8732(07)80046-5}
}
Abstract: Space-borne thermal infrared instruments working in the nadir geometry are providing spectroscopic measurements of species that impact on the chemical composition of the atmosphere and on the climate forcing: H2O, CO2, N2O, CH4, CFCs, O3, and CO. The atmospheric abundances obtained from the analysis of IMG/ADEOS measurements are discussed in order to demonstrate the potential scientific return to be expected from future missions using advanced infrared nadir sounders. Some strengths and limitations of passive infrared remote sensing from space are illustrated. © 2003 European Geosciences Union.
BibTeX:
@article{ClerbauxHadji-LazaroTurquetyEtAl2003,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and Mégie, G. and Coheur, P.-F.},
  title = {Trace gas measurements from infrared satellite for chemistry and climate applications},
  journal = {Atmospheric Chemistry and Physics},
  year = {2003},
  volume = {3},
  pages = {1495-1508},
  doi = {10.5194/acp-3-1495-2003}
}
Abstract: Atmospheric remote sensing from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. During this decade, remote sensors using the thermal infrared (TIR) spectral range have demonstrated their ability to sound the troposphere and provide global distribution for some of the key atmospheric species. This article illustrates three operational applications made possible with the IASI instrument onboard the European satellite MetOp, which opens new perspectives for routine observation of the evolution of atmospheric composition from space. © 2009 Académie des sciences.
BibTeX:
@article{ClerbauxTurquetyCoheur2010,
  author = {Clerbaux, C. and Turquety, S. and Coheur, P.},
  title = {Infrared remote sensing of atmospheric composition and air quality: Towards operational applications},
  journal = {Comptes Rendus - Geoscience},
  year = {2010},
  volume = {342},
  pages = {349-356},
  doi = {10.1016/j.crte.2009.09.010}
}
Abstract: We propose to combine the tropospheric measurements provided by the IASI and GOME2 instruments aboard METOP, together with data from ground-based stations, airborne and spaceborne remote sensors, along with atmospheric chemistry models (CTMs) in order to improve our knowledge of processes constraining the chemical composition of the troposphere and to study the regional and global scale air quality. The measurements of ozone (O 3), carbon monoxide (CO), nitrogen dioxide (NO2), formaldehyde (CH2O), and methane (CH4) will be used in conjunction with the 3D tropospheric LMDz-INCA, MOZART, IMAGES and CHIMERE CTM models, using data assimilation and inversion modeling techniques, to study the global distribution of these species and to derive improved emissions estimates. Before the METOP launch, all the tools developed in the framework of this project will be used to analyse the AURA TES and OMI tropospheric products. After the launch of METOP, the data provided by both satellites will then be analyzed with the CTMs. The resulting global distributions will be used to perform detailed studies of the role of biomass burning in the budget of tropospheric species, the emissions of ozone precursors, the role of convective transport of pollutants, and its consequences in terms of air quality.
BibTeX:
@conference{ClerbauxTurquetyHadji-LazaroEtAl2006,
  author = {Clerbaux, C. and Turquety, S. and Hadji-Lazaro, J. and Granier, C. and Hauglustaine, D. and Laval, S.S. and Beekmann, M. and Orphal, J. and Bergametti, G. and Camy-Peyret, C. and Payan, S. and Coheur, P. and De Mazière, M. and Müller, J.-F. and Prunet, P. and Klonecki, A.},
  title = {French/belgian scientific contribution to tropospheric studies using the metop sensors},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2006}
}
Abstract: Absorption cross sections of gas phase C60 and C70 in the 40 000 to 16 000 cm-1 region have been determined. The results are based on the combination of absorbance measurements of fullerene vapour, produced by the sublimation of samples in quartz double cells, and the vapour pressure measurements of the literature for solvent-free solid fullerenes. The gas phase cross sections are compared to those derived from molar extinction coefficients of C60 and C70 in hexane solutions and highlight the problems associated with the evaporation of solvent-containing fullerenes.
BibTeX:
@article{CoheurCarleerColin1996,
  author = {Coheur, P.F. and Carleer, M. and Colin, R.},
  title = {The absorption cross sections of C60 and C70 in the visible-UV region},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1996},
  volume = {29},
  pages = {4987-4995},
  doi = {10.1088/0953-4075/29/21/013}
}
Abstract: Infrared spectra recorded by the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) and the Interferometric Monitor for Greenhouse Gases (IMG) remote sensors have been analyzed by means of line-by-line radiative transfer calculations in order to evaluate the possibilities offered by solar occultation and by nadir instruments to monitor the cholorofluorocarbons (CFCs) and their substitutes. The reliability of the existing spectroscopic parameters has been examined, and it was found that only laboratory parameters measured at high resolution reproduce the satellite observations well. It is shown that solar occultation spectra can give information regarding the atmospheric abundance of CFC-113, in addition to the usual retrievals of CFC-11, CFC-12 and HCFC-22. Also, relying on existing emission scenarios, it is foreseen that future solar occultation experiments, such as the Atmospheric Chemistry Experiment (ACE), will be able to detect HCFC-142b and HFC-134a, from the year 2005 onward and at low tangent heights. As for the nadir-looking missions, it is found that CFC-11, CFC-12 and HCFC-22 can be retrieved from IMG spectra, provided that numerous measurements are averaged over space or time, thereby mitigating the usefulness of such measurements for determining surface sources. The improved geometrical scanning performances of the future nadir-looking Infrared Atmospheric Sounding Interferometer (IASI) and the Tropospheric Emission Spectrometer (TES), however, are shown to be more promising in this respect.
BibTeX:
@article{CoheurClerbauxColin2003,
  author = {Coheur, P.F. and Clerbaux, C. and Colin, R.},
  title = {Spectroscopic measurements of halocarbons and hydrohalocarbons by satellite-borne remote sensors},
  journal = {Journal of Geophysical Research D: Atmospheres},
  year = {2003},
  volume = {108},
  pages = {1-1}
}
Abstract: The geometry, ground-state, and optical properties of three isomers of C60Cl24, displaying Th or D2h symmetries were analyzed by means of semiempirical quantum-chemical calculations. Among these, the Th isomer was found to be the preferred thermodynamic product. The results bring some new information on the structure of halogenated fullerenes, which in turn were essential to determine the mechanism of halogen addition onto the carbon cages. Furthermore, the present analysis reinforces the usefulness of the semiempirical calculations of absorption spectra for the determination of the structural and the optical properties of fullerene derivatives.
BibTeX:
@article{CoheurLievinColinEtAl2003,
  author = {Coheur, P.F. and Liévin, J. and Colin, R. and Razbirin, B.},
  title = {Electronic and photophysical properties of C60Cl24},
  journal = {Journal of Chemical Physics},
  year = {2003},
  volume = {118},
  pages = {550-556},
  doi = {10.1063/1.1525807}
}
Abstract: This paper presents the first retrievals and validations of ozone vertical distributions from a set of high-resolution nadir thermal infrared measurements. These were obtained by the Interferometric Monitor for Greenhouse gases (IMG) instrument, which has operated on board the Japanese ADEOS platform between 1996 and 1997. The Optimal Estimation Method is used for the retrievals, along with a priori profile and covariance matrix built from model climatologies. We compare the retrieved IMG profiles with high-vertical-resolution ozone sonde measurements. Therefore we selected a set of IMG spectra collocated to within 3° of longitude and latitude with a representative distribution of ground-based stations. We demonstrate that thanks to the two to four independent pieces of vertical information contained in the spectroscopic measurements with a maximum sensitivity in the upper troposphere-middle stratosphere, the thermal infrared nadir sounders are able to capture most of the ozone spatial and temporal variations. In particular, the latitudinal variations of the stratospheric ozone maximum are well represented in the retrievals, as are the high ozone concentrations observed in the upper troposphere- lower stratosphere at northern midlatitudes during springtime. Ozone depletion events in the Arctic vortex are also well reproduced. The measurements provide an accurate view of the tropospheric ozone content, except when the latter is very low. A detailed error budget reveals that the major part of the error in the IMG retrieved ozone profile is due to the smoothing of the true profile by the averaging kernel matrix, with additional contributions associated with the measurement noise and the inaccurate knowledge of the temperature profile and of the Instrument Line Shape (ILS). Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{CoheurBarretTurquetyEtAl2005,
  author = {Coheur, P.-F. and Barret, B. and Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Clerbaux, C.},
  title = {Retrieval and characterization of ozone vertical profiles from a thermal infrared nadir sounder},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2005},
  volume = {110},
  article number = {D24303},
  pages = {1-12},
  doi = {10.1029/2005JD005845}
}
Abstract: An emission spectrum of hot water with a temperature of about 3000 K is obtained using an oxy-acetylene torch. This spectrum contains a very large number of transitions. The spectrum, along with previous cooler laboratory emission spectra and an absorption spectrum recorded from a sunspot, is analyzed in the 500-2000 cm -1 region. Use of a calculated variational linelist for water allows significant progress to be made on assigning transitions involving highly excited vibrational and rotational states. In particular emission from rotationally excited states up to J=42 and vibrational levels with up to eight quanta of bending motion are assigned.
BibTeX:
@article{CoheurBernathCarleerEtAl2005,
  author = {Coheur, P.-F. and Bernath, P.F. and Carleer, M. and Colin, R. and Polyansky, O.L. and Zobov, N.F. and Shirin, S.V. and Barber, R.J. and Tennyson, J.},
  title = {A 3000K laboratory emission spectrum of water},
  journal = {Journal of Chemical Physics},
  year = {2005},
  volume = {122},
  article number = {074307},
  doi = {10.1063/1.1847571}
}
Abstract: This work presents observations of a series of short-lived species in biomass burning plumes from the Infrared Atmospheric Sounding Interferometer (IASI), launched onboard the MetOp-A platform in October 2006. The strong fires that have occurred in the Mediterranean Basin - and particularly Greece - in August 2007, and those in Southern Siberia and Eastern Mongolia in the early spring of 2008 are selected to support the analyses. We show that the IASI infrared spectra in these fire plumes contain distinctive signatures of ammonia (NH3), ethene (C2H4), methanol (CH 3OH) and formic acid (HCOOH) in the atmospheric window between 800 and 1200 cm-1, with some noticeable differences between the plumes. Peroxyacetyl nitrate (CH3COOONO2, abbreviated as PAN) was also observed with good confidence in some plumes and a tentative assignment of a broadband absorption spectral feature to acetic acid (CH3COOH) is made. For several of these species these are the first reported measurements made from space in nadir geometry. The IASI measurements are analyzed for plume height and concentration distributions of NH3, C2H 4 and CH3OH. The Greek fires are studied in greater detail for the days associated with the largest emissions. In addition to providing information on the spatial extent of the plume, the IASI retrievals allow an estimate of the total mass emissions for NH3, C2H 4 and CH3OH. Enhancement ratios are calculated for the latter relative to carbon monoxide (CO), giving insight in the chemical processes occurring during the transport, the first day after the emission.
BibTeX:
@article{CoheurClarisseTurquetyEtAl2009,
  author = {Coheur, P.-F. and Clarisse, L. and Turquety, S. and Hurtmans, D. and Clerbaux, C.},
  title = {IASI measurements of reactive trace species in biomass burning plumes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {5655-5667},
  doi = {10.5194/acp-9-5655-2009}
}
Abstract: The absorption of solar light by atmospheric water vapor in the visible spectral region is analyzed by means of ground-based absorption Fourier transform spectroscopy, performed at high resolution in Brussels during summer 2001. Several microwindows between 14,000 and 18,000 cm-1, in which water vapor lines are well isolated from solar lines and other atmospheric trace gases absorptions, are examined. They are demonstrated to be adequate for the retrieval of the total water vapor column. Based on the retrievals, a detailed analysis of the water vapor line parameters published in the HITRAN database and recently reinvestigated by different groups is performed. The analysis focuses on the one hand on the comparison of the retrieved water vapor columns with in situ measurements, performed at the same time as the spectroscopic measurements and at the same location, and on the other hand on the quality of the spectral fits. It is shown that the discrepancies between the line lists affect significantly the results. In particular it is shown that the weaker lines, not measured in earlier laboratory experiments, do contribute at large zenith angles and need to be taken into account in order to better simulate the atmospheric spectra. The importance of the pressure broadening parameters is also highlighted. © 2003 Elsevier Ltd. All rights reserved.
BibTeX:
@article{CoheurClerbauxCarleerEtAl2003,
  author = {Coheur, P.-F. and Clerbaux, C. and Carleer, M. and Fally, S. and Hurtmans, D. and Colin, R. and Hermans, C. and Vandaele, A.C. and Barret, B. and De Mazière, M. and De Backer, H.},
  title = {Retrieval of atmospheric water vapor columns from FT visible solar absorption spectra and evaluation of spectroscopic databases},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2003},
  volume = {82},
  pages = {133-150},
  doi = {10.1016/S0022-4073(03)00150-X}
}
Abstract: The geometry and electronic structure of three C60 derivatives (C60Cl6, C60Ph5Cl and C60Ph5H) are studied by means of spectroscopic measurements in cyclohexane solution and semi-empirical Hartree-Fock quantum-chemical calculations. A good agreement between observed and simulated spectra is reported. Based on the latter, the importance of symmetry and nature of the functional groups on the properties of the C60 cages is discussed.
BibTeX:
@article{CoheurCornilDosSantosEtAl1999,
  author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Janot, J.-M. and Seta, P. and Leach, S. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.},
  title = {Photophysical properties of C60Cl6, C60Ph5Cl and C60Ph5H},
  journal = {Synthetic Metals},
  year = {1999},
  volume = {103},
  pages = {2407-2410},
  doi = {10.1016/S0379-6779(98)00250-1}
}
Abstract: The photophysical properties of hexa-functionalized C60 derivatives (C60Cl6, C60Ph5Cl, C60Ph5H, and two C60Ph5OH isomers) have been investigated by means of UV-visible absorption and fluorescence spectroscopy in cyclohexane solution and quantum-chemical calculations derived from semiempirical Hartree-Fock approaches. A very good agreement is obtained between the measured absorption and fluorescence spectra and the calculated excitation energies, thus allowing for a detailed assignment of the optical features. The effects of symmetry and chemical nature of the functional groups on the ground-state and spectroscopic properties of the C60 derivatives are discussed. © 2000 American Institute of Physics.
BibTeX:
@article{CoheurCornilDosSantosEtAl2000,
  author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.},
  title = {Photophysical properties of hexa-functionalized C60 derivatives: Spectroscopic and quantum-chemical investigations},
  journal = {Journal of Chemical Physics},
  year = {2000},
  volume = {112},
  pages = {8555-8566},
  doi = {10.1063/1.481485}
}
Abstract: The photophysics of six multiply phenylated C70 derivatives [C70Ph2, C70Ph4, C70Ph6 (two regioisomers), C70Ph8 and C70Ph10] have been investigated by means of steady state spectroscopy in cyclohexane solution and quantum-chemical calculations derived from semiempirical Hartree-Fock approaches. There is good agreement between the measured absorption spectra and the INDO/SCI calculated excitation energies for each derivative. The foregoing results and some additional ground state properties calculated at the AMI level have been used to predict that the perturbation of the π electronic system of the cage results in significant changes in the photophysics of the fullerene derivatives. The effects of conjugation and spatial localization of the HOMO and LUMO orbitals on the energy of the first electronic transition are discussed in greater detail. © 2000 American Institute of Physics.
BibTeX:
@article{CoheurCornilDosSantosEtAl2000a,
  author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.},
  title = {Photophysical properties of multiply phenylated C70 derivatives: Spectroscopic and quantum-chemical investigations},
  journal = {Journal of Chemical Physics},
  year = {2000},
  volume = {112},
  pages = {6371-6381},
  doi = {10.1063/1.481198}
}
Abstract: The radiative properties of water vapor play an important role in the physical and chemical processes occurring in the atmosphere. Accurate knowledge of the line parameters for this species is therefore needed. This work presents new measurements of water vapor line parameters in the 26000-13000 cm-1 spectral region. The measurements were obtained by combining a high-resolution Fourier transform spectrometer with a long-path absorption cell, thus allowing the observation of very weak, previously unobserved, lines. A total of more than 9000 lines have been identified and their position, integrated cross section and self-broadening parameter have been determined. The dependence of the line parameters on nitrogen buffer gas pressure (0-800 hPa) has also been studied. The complete line list presented here is primarily compared to the HITRAN spectroscopic database, most frequently used in atmospheric calculations. © 2002 Elsevier Science Ltd. All rights reserved.
BibTeX:
@article{CoheurFallyCarleerEtAl2002,
  author = {Coheur, P.-F. and Fally, S. and Carleer, M. and Clerbaux, C. and Colin, R. and Jenouvrier, A. and Mérienne, M.-F. and Hermans, C. and Vandaele, A.C.},
  title = {New water vapor line parameters in the 26000-13000 cm-1 region},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2002},
  volume = {74},
  pages = {493-510},
  doi = {10.1016/S0022-4073(01)00269-2}
}
Abstract: This work reports on the analysis of the near-UV and visible absorption spectrum of water vapor, obtained by combining a high-resolution FT spectrometer and a long path White multiple-reflection cell (total path length of 602 m). A large number of water vapor lines belonging to highly excited vibrational levels (polyads up to 8 v) are identified. Most of these lines have not been observed previously and do not appear in the spectroscopic databases HITRAN and GEISA, widely used for atmospheric calculations. All identified lines are fitted with a Voigt profile using the WSPECTRA program and their cross section and self-broadening parameters at 291 K are determined. A particular attention is given to the integrated cross section over the total spectral range investigated (25000-20000 cm-1), in order to estimate the contribution of the weak UV-visible water vapor absorption lines to the earth's radiation balance. Preliminary measurements of cross section in the 20000-16000 cm-1 spectral range are also presented.
BibTeX:
@conference{CoheurFallyVandaeleEtAl2001,
  author = {Coheur, P.-F. and Fally, S. and Vandaele, A.C. and Hermans, C. and Jenouvrier, A. and Carleer, M. and Mérienne, M.-F. and Clerbaux, C. and Colin, R.},
  title = {Absolute intensities of water vapor lines in the near ultraviolet and visible regions},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2001},
  volume = {4168},
  pages = {97-105},
  doi = {10.1117/12.413853}
}
Abstract: In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACEFTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm-1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.
BibTeX:
@article{CoheurHerbinClerbauxEtAl2007,
  author = {Coheur, P.-F. and Herbin, H. and Clerbaux, C. and Hurtmans, D. and Wespes, C. and Carleer, M. and Turquety, S. and Rinsland, C.P. and Remedios, J. and Hauglustaine, D. and Boone, C.D. and Bernath, P.F.},
  title = {ACE-FTS observation of a young biomass burning plume: First reported measurements of C2H4, C3H6O, H 2CO and PAN by infrared occultation from space},
  journal = {Atmospheric Chemistry and Physics},
  year = {2007},
  volume = {7},
  pages = {5437-5446},
  doi = {10.5194/acp-7-5437-2007}
}
Abstract: On the basis of previously published optical data (Colin and Douglas, Canad. J. Phys. 46, 61-73 (1968)) for three isotopes (14NH+, 15NH+ and 14ND+) of the NH+ ion, a study of the perturbations occurring between the X2Π and a4Σ- states has been carried out using matrix diagonalization techniques. This makes it possible to derive for both states equilibrium rotational and vibrational constants, from which RKR potential energy functions, vibrational overlap integrals, electronic interaction parameters, and a pure electronic term value for the a4Σ- state are deduced. © 1989.
BibTeX:
@article{Colin1989,
  author = {Colin, R.},
  title = {Perturbations between the X2Π and a4Σ- states of the NH+ ion},
  journal = {Journal of Molecular Spectroscopy},
  year = {1989},
  volume = {136},
  pages = {387-401},
  doi = {10.1016/0022-2852(89)90344-5}
}
Abstract: A rotational analysis has been carried out on the 3Π 1 and 3Π0 sub-bands of the 1-0 band of the A 3Π-X3Σ spectrum of SO obtained previously. A perturbation present on the v′ = 1, J′ = 15 level of the F 2(3Π1) component of the A3Π state is shown to be consistent with that arising from interaction with a 3Δ state. Using calculations of Dixon et al., coupled with an empirical correction to the calculated term value of the 3Δ state, a crude potential is constructed which would cross the A state at v′ = 1.
BibTeX:
@article{Colin1982,
  author = {Colin, R.},
  title = {Spectrum of SO. Evidence for a new 3δ state},
  journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics},
  year = {1982},
  volume = {78},
  pages = {1139-1147},
  doi = {10.1039/F29827801139}
}
BibTeX:
@article{Colin1964,
  author = {Colin, R.},
  title = {Thermodynamic study of germanium monotelluride using a mass spectrometer},
  journal = {Journal of Physical Chemistry},
  year = {1964},
  volume = {68},
  pages = {428-430}
}
Abstract: The B2Σ+-X2Σ+ (violet system) electronic transition of the 13C15N free radical was recorded with a Fourier transform spectrometer. The 0-0, 1-1, 1-0, 0-1 and 1-2 bands were rotationally analyzed to obtain spectroscopic constants. There have been no previous measurements of any electronic transitions for the 13C15N isotopologue. © 2014 Elsevier Inc. All rights reserved.
BibTeX:
@article{ColinBernath2014,
  author = {Colin, R. and Bernath, P.F.},
  title = {Rotational analysis of the B2Σ+-X 2Σ+ transition of the 13C15N molecule},
  journal = {Journal of Molecular Spectroscopy},
  year = {2014},
  volume = {302},
  pages = {34-35},
  doi = {10.1016/j.jms.2014.06.006}
}
Abstract: Emission spectra of the A 2Π-X 2Σ + (red) and B 2Σ +-X 2Σ + (violet) systems of the 12C 15N molecule have been investigated in the 4500-26 000 cm -1 spectral region at high resolution using a Fourier transform spectrometer. In all, 22 bands of the A-X system and six bands of the B-X system have been rotationally analyzed providing a set of molecular constants for the v″ = 0-5, v′ = 0-4 and v′ = 0-3 levels of the X, A and B states, respectively. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{ColinBernath2012,
  author = {Colin, R. and Bernath, P.F.},
  title = {High resolution Fourier transform emission spectroscopy of the A 2Π-X 2Σ + and B 2Σ +-X 2Σ + systems of the 12C 15N free radical},
  journal = {Journal of Molecular Spectroscopy},
  year = {2012},
  volume = {273},
  pages = {30-33},
  doi = {10.1016/j.jms.2012.01.007}
}
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-5) state of the CH radical. They are derived from a fit of previously published data and additional lines taken from infrared solar spectra recorded on orbit and from new laboratory IR emission data. © 2010 Elsevier Inc. All rights reserved.
BibTeX:
@article{ColinBernath2010,
  author = {Colin, R. and Bernath, P.F.},
  title = {Revised molecular constants and term values for the X2Π state of CH},
  journal = {Journal of Molecular Spectroscopy},
  year = {2010},
  volume = {263},
  pages = {120-122},
  doi = {10.1016/j.jms.2010.06.013}
}
BibTeX:
@article{ColinCoheurKiselevaEtAl2002,
  author = {Colin, R. and Coheur, P.-F. and Kiseleva, M. and Vandaele, A.C. and Bernath, P.F.},
  title = {Spectroscopic constants and term values for the X2πi state of OH (v = 0-10)},
  journal = {Journal of Molecular Spectroscopy},
  year = {2002},
  volume = {214},
  pages = {225-226},
  doi = {10.1006/jmsp.2002.8591}
}
Abstract: The 0-0, 1-1, 2-2, 3-3 and 4-4 bands of the b1Σ+-X3Σ- transition of the PF molecule have been observed in the afterglow produced when PF5 + He (or Ar) is pumped rapidly through a microwave discharge. Measurements of the lines of the sR and oP branches of the strong 0-0 band, which lies at 7483 Å, allows the calculation of Te(b1Σ+) = 13 353.91 ± 0.05 cm-1 and the derivation of the position of all previously known singlet states of this molecule with respect to the triplet ground state. © 1972.
BibTeX:
@article{ColinDevillersPrevot1972,
  author = {Colin, R. and Devillers, J. and Prevot, F.},
  title = {The b1Σ+-X3Σ- band system of PF},
  journal = {Journal of Molecular Spectroscopy},
  year = {1972},
  volume = {44},
  pages = {230-235},
  doi = {10.1016/0022-2852(72)90102-6}
}
Abstract: The atomization energies: D°0(InS) = 67.9 ± 3.5; D°0(InSe) = 57.7 ± 3.5; D °0(InTe) = 50.6 ± 3.5; ΔH °0(In2S) = 148.2 ± 4.0; ΔH°0(In2Se) = 132.7 ± 4.0; ΔH°0(In2Te) = 110.8 ± 4.0; ΔH°0(In2S2) = 224.5 ± 10.0; ΔH°0(In2Se 2) = 200.5 ± 10.0; ΔH°0(In2Te2) = 173.2 ± 10.0 and ΔH0(InTe2) = 107.4 ± 4.0 kcal/mole were determined. The heat of formation of In2S3(s) was deduced : ΔH°298, f(In2S3) = -82.8 ± 4.5 kcal/mole. The dissociation energies D°0(Se2) = 73.6 ± 2.0 and D°0(Te2) = 55.9 ± 2.0 kcal/mole were also measured.
BibTeX:
@article{ColinDrowart1968,
  author = {Colin, R. and Drowart, J.},
  title = {Mass spectrometric determination of dissociation energies of gaseous indium sulphides, selenides and tellurides},
  journal = {Transactions of the Faraday Society},
  year = {1968},
  volume = {64},
  pages = {2611-2621},
  doi = {10.1039/TF9686402611}
}
Abstract: In a mass-spectrometric investigation of the vapour in equilibrium with solid SnSe and solid SnTe, a number of reaction enthalpies were measured, which, combined with known thermochemical data, yield: (Equation Presented) The dissociation energies are compared with spectroscopic data.
BibTeX:
@article{ColinDrowart1964,
  author = {Colin, R. and Drowart, J.},
  title = {Thermodynamic study of tin selenide and tin telluride using a mass spectrometer},
  journal = {Transactions of the Faraday Society},
  year = {1964},
  volume = {60},
  pages = {673-683},
  doi = {10.1039/tf9646000673}
}
Abstract: A mass-spectrometric investigation of the vapor in equilibrium with solid SnS, solid PbS, and a mixture of SnS and PbS has yielded the following reaction enthalpies: SnS(s)→SnS(g) ΔH2980 = 52.6±1.6 kcal/mole 2SnS(s)→Sn2S2(g) 56.5±5.0 PbS(s)→PbS(g) 55.7±1.6 2PbS(s)→Pb 2S2(g) 66.6±5.0 PbS(g)→Pb(g) + 1/2 S 2(g) 28.8±2.6 Sn2S2(g)→2SnS(g) 48.7±5.0 Pb2S2(g)→2PbS(g) 44.8±5.0 SnPbS2(g)→SnS(g)+PbS(g) 46.5±5.0. The dissociation energies of gaseous SnS and PbS were determined to be D00 (SnS) = 110.1±3.0 kcal/mole, D00(PbS) = 79.1±2.8 kcal/mole and are compared with the spectroscopically determined values.
BibTeX:
@article{ColinDrowart1962,
  author = {Colin, R. and Drowart, J.},
  title = {Thermodynamic study of tin sulfide and lead sulfide using a mass spectrometer},
  journal = {The Journal of Chemical Physics},
  year = {1962},
  volume = {37},
  pages = {1120-1125},
  doi = {10.1063/1.1733223}
}
Abstract: The evaporation of tin oxide SnO2 and mixtures of tin and tin oxide was studied. The vaporization reactions are (Equation Presented) The dissociation energy of the molecule SnO was determined: D°0 = 126.5±2.0 kcal/mole; as well as the polymerization energies ΔH 298° = 66.8±4, 136.5±5, 207.6±5 kcal/mole for (SnO)2, (SnO)3 snd (SnO)4 respectively. A re-interpretation of the total vapour pressures given in the literature was made. The presence of the polymeric molecules is the cause of previously unexplained differences.
BibTeX:
@article{ColinDrowartVerhaegen1965,
  author = {Colin, R. and Drowart, J. and Verhaegen, G.},
  title = {Mass-spectrometric study of the vaporization of tin oxides: Dissociation energy of SnO},
  journal = {Transactions of the Faraday Society},
  year = {1965},
  volume = {61},
  pages = {1364-1371},
  doi = {10.1039/tf9656101364}
}
Abstract: CaS, SrS and BaS have been evaporated from molybdenum Knudsen cells and the emerging molecular beam analyzed by mass spectrometry. From the composition of the vapour, the following thermodynamic properties of the gaseous species are obtained: D°0(S2) = 97±5 kcal mole-1 in agreement with a proposed value of D°0(S2) = 99.4±2.5 kcal mole-1 which takes into account data on dissociation energies of GeS, SnS, PbS, and spectroscopic data on D°0(S2). Further the values, D°0(CaS) = 73.7±4.5 kcal; D°0(SrS) = 74.1±4.5 kcal; D°0(BaS) = 94.7±4.5 kcal; ΔH(dim. BaS) = 113.9±5 kcal; ΔH°298 vap (CaS) = 14.0±5 kcal; ΔH°298 vap (SrS) = 143.0±5 kcal; ΔH°298 vap (BaS) = 122.5±5 kcal mole-1 were measured. Oxides in some of the samples permitted one to measure D°0(CaO) = 84.4±6 kcal; D°0(SrO) = 92.2±6 kcal; D°0(BaO) = 130.4±6 kcal from the equilibrium with SO; simultaneously the value D°0(SO) = 123.5 kcal mole-1 was confirmed.
BibTeX:
@article{ColinGoldfingerJeunehomme1964,
  author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.},
  title = {Mass-spectrometric studies of the vaporization of the sulphides of calcium, strontium and barium. The dissociation energy of S2 and SO},
  journal = {Transactions of the Faraday Society},
  year = {1964},
  volume = {60},
  pages = {306-316},
  doi = {10.1039/tf9646000306}
}
Abstract: IT is of interest to obtain data on the lattice energy, ΔH 00[at.], of solids, and dissociation energies, D 00, of gaseous molecules of whole groups of compounds, such as homonuclear molecules1, oxides2, sulphides 2, etc., and to study the variation of these properties, or the ratio of these magnitudes, ΔH00[at.]/D0 0 = α, as a function of the electronic structure of the constituting atoms. An interesting case is that of the sulphides of transition elements. © 1962 Nature Publishing Group.
BibTeX:
@article{ColinGoldfingerJeunehomme1962,
  author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.},
  title = {Existence of gaseous sulphides of the transition elements: Dissociation energy of gaseous MnS},
  journal = {Nature},
  year = {1962},
  volume = {194},
  pages = {282-283},
  doi = {10.1038/194282a0}
}
Abstract: THE disagreement between second- and third-law values of the dissociation energy of S2(D00(S2)) obtained from equilibrium measurements was emphasized many years ago1. A relationship was also pointed out between the heat of combustion of SO, D 00(O2), D00(SO) and D00(S2), which should permit one to choose one of the values allowed by observed predissociations for D0 0(S2) and D00(SO). Recent measurements2 do not seem to settle the question3. © 1960 Nature Publishing Group.
BibTeX:
@article{ColinGoldfingerJeunehomme1960,
  author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.},
  title = {Mass spectrometric investigation of the vaporization of sulphides and the dissociation energy of S2},
  journal = {Nature},
  year = {1960},
  volume = {187},
  pages = {408-409},
  doi = {10.1038/187408a0}
}
Abstract: The ionization potential of the BeH molecule is derived from a few Rydberg states observed in the absorption spectrum and from "ab initio" calculations of the energies of the ground states of the BeH and BeH+ molecules at their equilibrium distances. The values are in agreement and yield PI(BeH, X2Σ+) = 66 100 ± 500 cm-1. © 1974.
BibTeX:
@article{ColinGreefGoethalsEtAl1974,
  author = {Colin, R. and de Greef, D. and Goethals, P. and Verhaegen, G.},
  title = {The ionization potential of the BeH molecule},
  journal = {Chemical Physics Letters},
  year = {1974},
  volume = {25},
  pages = {70-73},
  doi = {10.1016/0009-2614(74)80334-9}
}
Abstract: The analysis of high resolution absorption spectra of the C2H2, C2D213C2H2 and C2HD molecules in the region 1205-1255 A has been achieved. The results, combined with available theoretical relations, have led to a complete interpretation of the features observed in that region in terms of several Renner-Teller interactions involving two close-lying electronic states, G and H, and the two bending vibrations of the molecule. Upper state parameters ɛ and ω satisfying isotopic relations, are derived from the interpretation. © 1979 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{ColinHermanKopp1979,
  author = {Colin, R. and Herman, M. and Kopp, I.},
  title = {Renner-teller interactions in the acetylene molecule},
  journal = {Molecular Physics},
  year = {1979},
  volume = {37},
  pages = {1397-1412},
  doi = {10.1080/00268977900101031}
}
Abstract: A new band system lying in the region 8500-8970 Å and composed of twelve single-headed violet-degraded bands has been photographed at medium resolution from a microwave discharge of He + PI3. The bands are assigned to the b 0+-X10+ transition of PI and vibrational analysis leads to ω′e = 426.30, ω′ex′c = 1.40, ω″e = 399.90, ω″ex″e = 1.35 and Te = 11532.28cm-1. © 1982.
BibTeX:
@article{ColinHermanPrevot1982,
  author = {Colin, R. and Herman, M. and Prevot, F.},
  title = {The bO+X1O+ band system of the PI molecule},
  journal = {Chemical Physics Letters},
  year = {1982},
  volume = {91},
  pages = {213-216},
  doi = {10.1016/0009-2614(82)83644-0}
}
Abstract: We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from two satellite instruments (ACE-FTS and OSIRIS) with long-term in situ measurements from aircraft (MOZAIC, CR-AVE, PRE-AVE, PEM Tropics, and TC4) and ozonesondes. A global chemical transport model (GEOS-Chem) is used to guide the evaluation and to relate sparse in situ measurements with the satellite retrievals. Both satellite retrievals generally reproduce broad ozone features in the upper troposphere such as summer enhancements in the northern subtropics and larger concentrations over the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (10-13%) and OSIRIS (5%) relative to aircraft and ozonesonde observations. More uncertain evidence suggests that nitric acid from ACE-FTS has a positive mean bias of 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using ACE-FTS satellite measurements of O3 and HNO3. The resulting value of 196 (+34, -61) mol/mol is in broad agreement with model simulations. Higher OPE values inferred from ACE-FTS over the tropical Pacific (249 (+21, -68) mol/mol) than the tropical Atlantic (146 (+16, -41) mol/mol) reflect increasing ozone production efficiency with decreasing pollution. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{CooperMartinSauvageEtAl2011,
  author = {Cooper, M. and Martin, R.V. and Sauvage, B. and Boone, C.D. and Walker, K.A. and Bernath, P.F. and McLinden, C.A. and Degenstein, D.A. and Volz-Thomas, A. and Wespes, C.},
  title = {Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D12306},
  doi = {10.1029/2010JD015056}
}
Abstract: This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument with a global chemical transport model (GEOS-Chem). GEOS-Chemand IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{CooperMartinWespesEtAl2014,
  author = {Cooper, M. and Martin, R.V. and Wespes, C. and Coheur, P.-F. and Clerbaux, C. and Murray, L.T.},
  title = {Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {10068-10079},
  doi = {10.1002/2014JD021907}
}
Abstract: The 1s‐ionization potentials of carbon and oxygen atoms have been calculated. The effects due to the relaxation of the valence orbitals have been taken into account at all levels of the calculations (Hartree‐Fock, relativistic, and correlation energies). The results obtained are IP(1s, C3P) = 295.2 eV and IP (1s, O3P) = 543.5 eV. Exchange‐induced splittings have also been determined: ΔE(C+, 1s(4P – 2P)) = 3.34 eV and ΔE(O +, 1s(4P – 2P)) = 4.43 eV. These predictions are compared to analogous experimental results. Copyright © 1973 John Wiley &amp; Sons, Inc.
BibTeX:
@article{CorvilainVerhaegen1973,
  author = {Corvilain, S. and Verhaegen, G.},
  title = {K‐shell binding energies in C and O},
  journal = {International Journal of Quantum Chemistry},
  year = {1973},
  volume = {7},
  pages = {69-81},
  doi = {10.1002/qua.560070711}
}
Abstract: Large-basis-set calculations of near Hartree-Fock accuracy were performed on CO+(1σ-hole 2Σ+) and CO+)2σ-hole, 2Σ+); correlation energies for these systems and for CO were calculated using an atoms-in-molecule approach, relativistic energies and vibrational structure corrections were also considered. The results are: IP(CO, 1σ) = 542.4 (542.57) eV, IP(CO,2σ) = 297.0 (296.24) cV, Dc(CO, 1Σ+) = 10.8 (11.1) Ev, D3(CO+, 1σ, 2Σ+) = 11.9 eV, De(CO+, 2σ, 2Σ+) = 9.1 eV, where IP and De stand respectively for ionization potential and dissociation energy, and where the numbers in parentheses refer to the most recent experimental values. The electron transfers resulting from the ionization of inner-shell electrons are discussed. Finally a quantitative correlation is developed correlating absolute chemical shifts to charge densities. Agreement between the calculated values and those derived from the correlation is quite satisfactory. © 1977.
BibTeX:
@article{Corvilain-BergerVerhaegen1977,
  author = {Corvilain-Berger, S. and Verhaegen, G.},
  title = {Theoretical determination of the ionization potentials of the 1σ and 2σ electrons of CO(1Σ+)},
  journal = {Chemical Physics Letters},
  year = {1977},
  volume = {50},
  pages = {468-475},
  doi = {10.1016/0009-2614(77)80368-0}
}
Abstract: The v6, v17, and v21 fundamental bands of dimethyl ether have been assigned and rotationally analyzed. The spectra used were recorded at 0.005 cm−1 spectral resolution with a Fourier-transform spectrometer coupled to a supersonic molecular beam leading to a rotational temperature of about 70 K. The v6 and v21 bands do not seem to be perturbed and the analysis of the rotational structure leads to band centers located at 933.906 6(9) and 1 103.951(1) cm−1, respectively, and to accurate rotational and centrifugal distortion constants. For the v17 band at 2817.385(2) cm−1, only the P and R branches could be assigned. © 2002 Elsevier Science (USA).
BibTeX:
@article{CoudertCarcabalChevalierEtAl2002,
  author = {Coudert, L.H. and Çarçabal, P. and Chevalier, M. and Broquier, M. and Hepp, M. and Herman, M.},
  title = {High-resolution analysis of the v6, v17, and v21 bands of dimethyl ether},
  journal = {Journal of Molecular Spectroscopy},
  year = {2002},
  volume = {212},
  pages = {203-207},
  doi = {10.1006/jmsp.2002.8541}
}
Abstract: The series solution method used by H. Cox, S. J. Smith and B. T. Sutcliffe (1994, Phys. Rev. A, 49, 4520, 4533) to obtain extremely accurate eigenvalues and eigenvectors for the lowest singlet and triplet states of low Z helium-like systems has been applied to the ground 1S state of the positronium negative ion. Secular determinatnts of up to size 2847 × 2847 have been solved to give a ground state energy of 0·262 005 070 231 742 au. This agrees to 12 decimal places with the most accurate literature value reported by Y. K. Ho (1993, Phys. Rev. A, 48, 4780). Various expectation values involving the interparticle distances have also been evaluated. We estimate the positron-electron annihilation rate Г as 2·086 1223 ns-1. This is in agreement with the most accurate literature value of 2·086 1222 ± 5 × 10-7 (Ho, 1993, Phys. Rev. A, 48, 4780) and the experimental value of 2·09 ± 9 × 10-2 (Mills, 1983, Phys. Rev. Lett., 50, 671). © 1996 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{CoxSinclairSmithEtAl1996,
  author = {Cox, H. and Sinclair, P.E. and Smith, S.J. and Sutcliffe, B.T.},
  title = {Some calculations on the ground 1S state of the positronium negative ion},
  journal = {Molecular Physics},
  year = {1996},
  volume = {87},
  pages = {399-406},
  doi = {10.1080/00268979600100261}
}
Abstract: This paper presents a discussion of some programs written in the computer algebra language Maple and in the C language for solving the body-fixed Schrödinger equation for three particles with Coulomb interaction in perimetric coordinates by means of a series solution. © 1994.
BibTeX:
@article{CoxSmithSutcliffe1994,
  author = {Cox, H. and Smith, S.J. and Sutcliffe, B.T.},
  title = {An application of the computer algebra system Maple for calculations on atomic and molecular systems},
  journal = {Computer Physics Communications},
  year = {1994},
  volume = {84},
  pages = {186-200},
  doi = {10.1016/0010-4655(94)90211-9}
}
Abstract: The series solution method developed by Pekeris [Phys. Rev. 112, 1649 (1958); 115, 1216 (1959)] for the Schrödinger equation for two-electron atoms, as generalized by Frost et al. [J. Chem. Phys. 41, 482 (1964)] to handle any three particles with a Coulomb interaction, has been used. The wave function is expanded in triple orthogonal set in three perimetric coordinates. From the Schrödinger equation an explicit recursion relation for the coefficients in the expansion is obtained, and the vanishing of the determinant of these coefficients provides the condition for the energy eigenvalues and for the eigenvectors. The Schrödinger equation is solved and the matrix elements are produced algebraically by using the computer algebra system maple. The substitutions for a particular atom and diagonalization were performed by a program written in the c language. Since the determinant is sparse, it is possible to go to the order of 1078 as Pekeris did without using excessive memory or computer CPU time. By using a nonlinear variational parameter in the expression used to remove the energy, nonrelativistic energies, within the fixed-nucleus approximation, have been obtained. For the ground-state singlet 1 1S state, this is of the accuracy claimed by Frankowski and Pekeris [Phys. Rev. 146, 46 (1966); 150, 366(E) (1966)] using logarithmic terms for Z from 1 to 10, and for the triplet 2 3S state, energies have been obtained to 12 decimal places of accuracy, which, with the exception of Z=2, are lower than any previously published, for all Z from 3 to 10. © 1994 The American Physical Society.
BibTeX:
@article{CoxSmithSutcliffe1994a,
  author = {Cox, H. and Smith, S.J. and Sutcliffe, B.T.},
  title = {Some calculations on the ground and lowest-triplet state of helium in the fixed-nucleus approximation},
  journal = {Physical Review A},
  year = {1994},
  volume = {49},
  pages = {4520-4532},
  doi = {10.1103/PhysRevA.49.4520}
}
Abstract: The method described in the preceding paper for the solution of two-electron atoms, which was used to calculate the 1 1S and 2 3S states of helium and heliumlike atoms within the fixed-nucleus approximation, has been applied to the case where all three particles are in relative motion. The solutions in the present case automatically include the effects of the mass polarization term and are compared with the results obtained for the term by using first-order perturbation theory with the fixed-nucleus wave functions. The input data for a particular atom consist of the atomic number, as before, but now the corresponding mass of the nucleus must be given also. Nonrelativistic energies with the nuclear mass included in the calculation have been obtained for the 1 1S and 2 3S states for Z ranging from 1 to 10. The energy with the nucleus in motion can be expressed only to eight significant figures (SF's) given the accuracy with which the relevant physical constants are known at present. All the results given here are computed as if these constants were known to ten SF's so that errors not incurred due to rounding. Convergence of the energies to ten SF's for both the singlet and triplet state was reached with a matrix of size 444 for Z values from 2 to 10. Convergence for the H- ion was a little slower. © 1994 The American Physical Society.
BibTeX:
@article{CoxSmithSutcliffe1994b,
  author = {Cox, H. and Smith, S.J. and Sutcliffe, B.T.},
  title = {Some calculations on the ground and lowest-triplet state of the helium isoelectronic sequence with the nucleus in motion},
  journal = {Physical Review A},
  year = {1994},
  volume = {49},
  pages = {4533-4539},
  doi = {10.1103/PhysRevA.49.4533}
}
Abstract: The A1Σ+-X1Σ+ band system of BeH+, BeD+, and BeT+ has been photographed at high resolution and rotationally analyzed. Together with literature data (W. W. Watson and R. F. Humphreys, Phys. Rev. 52, 318-321 (1937)) for υ″ = 7-10 of BeH+, the data set samples vibrational levels that extend up to ≈2/3 and ≈1/2 of the well depths of the X and A states, respectively. The measured line positions were employed in a global least-squares fit of the molecular Hamiltonians for the two states that take account of Born-Oppenheimer breakdown effects and in which a modified Lennard-Jones (MLJ) function is employed for the potential energy. The fit reproduces the measurements to within the estimated accuracy (≈0.05 cm-1). © 1997 Academic Press, Inc.
BibTeX:
@article{CoxonColin1997,
  author = {Coxon, J.A. and Colin, R.},
  title = {Born-Oppenheimer breakdown effects from rotational analysis of the A1Σ+-x1Σ+ band system of BeH+, BeD+, and BeT+},
  journal = {Journal of Molecular Spectroscopy},
  year = {1997},
  volume = {181},
  pages = {215-223},
  doi = {10.1006/jmsp.1996.7153}
}
Abstract: Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by EUMETSAT onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; and (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfil these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; and (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interference between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential to strongly benefit the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative. © Author(s) 2014.
BibTeX:
@article{CrevoisierClerbauxGuidardEtAl2014,
  author = {Crevoisier, C. and Clerbaux, C. and Guidard, V. and Phulpin, T. and Armante, R. and Barret, B. and Camy-Peyret, C. and Chaboureau, J.-P. and Coheur, P.-F. and Crépeau, L. and Dufour, G. and Labonnote, L. and Lavanant, L. and Hadji-Lazaro, J. and Herbin, H. and Jacquinet-Husson, N. and Payan, S. and Péquignot, E. and Pierangelo, C. and Sellitto, P. and Stubenrauch, C.},
  title = {Towards IASI-New Generation (IASI-NG): Impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4367-4385},
  doi = {10.5194/amt-7-4367-2014}
}
BibTeX:
@article{CsizmadiaHarrisonMoskowitzEtAl1967,
  author = {Csizmadia, I.G. and Harrison, M.C. and Moskowitz, J.W. and Sutcliffe, B.T.},
  title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Graussian type functions},
  journal = {Theoretica Chimica Acta},
  year = {1967},
  volume = {7},
  pages = {156},
  doi = {10.1007/BF01151918}
}
Abstract: This paper (Part I) describes the theoretical and computational bases of some non-empirical calculations on small organic molecules to be reported in later papers (Parts II et seq). Approximate solutions for the usual fixed nucleus electronic Hamiltonian, in the term of wave functions composed of Slater determinants, are discussed, with particular emphasis on their computational utility. Possible choices of basis functions, from which to form the determinants are examined, and the advantages of Gaussian type functions (GTF) centered on the component atoms are pointed out. Some of the properties of molecules which can be calculated using such approximate wave functions are outlined. Finally an attempt is made to discuss the current limitations of non-empirical calculations of the type described here, and some guesses are made about their future. Brief outlines as a set of appendices are given of the mathematical formalism and computational details of the calculations. © 1966 Springer-Verlag.
BibTeX:
@article{CsizmadiaHarrisonMoskowitzEtAl1966,
  author = {Csizmadia, I.G. and Harrison, M.C. and Moskowitz, J.W. and Sutcliffe, B.T.},
  title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part I. Introductory review and mathematical formalism},
  journal = {Theoretica Chimica Acta},
  year = {1966},
  volume = {6},
  pages = {191-216},
  doi = {10.1007/BF02394698}
}
Abstract: This paper (Part I) describes the theoretical and computational bases of some non-empirical calculations on small organic molecules to be reported in later papers (Parts II et seq). Approximate solutions for the usual fixed nucleus electronic Hamiltonian, in the term of wave functions composed of Slater determinants, are discussed, with particular emphasis on their computational utility. Possible choices of basis functions, from which to form the determinants are examined, and the advantages of Gaussian type functions (GTF) centered on the component atoms are pointed out. Some of the properties of molecules which can be calculated using such approximate wave functions are outlined. Finally an attempt is made to discuss the current limitations of non-empirical calculations of the type described here, and some guesses are made about their future. Brief outlines as a set of appendices are given of the mathematical formalism and computational details of the calculations. © 1966 Springer-Verlag.
BibTeX:
@article{CsizmadiaHarrisonMoskowitzEtAl1966a,
  author = {Csizmadia, I.G. and Harrison, M.C. and Moskowitz, J.W. and Sutcliffe, B.T.},
  title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part I. Introductory review and mathematical formalism},
  journal = {Theoretica Chimica Acta},
  year = {1966},
  volume = {6},
  pages = {191-216},
  doi = {10.1007/BF02584315}
}
Abstract: Non-empirical molecular quantum chemical calculations were performed on formyl fluoride (HCOF) in the LCAO-MO-SCF framework using Gaussian type functions as atomic orbitals. In the first half of this paper a quantitative correlation has been established between some of the calculable molecular properties of HCOF and the size of the basis set used. It is hoped that the basic conclusions are general enough to be applicable to calculations of similar type on different molecules. The second part consists of a preliminary SCF study of HCOF in its electronic ground state. © 1966 Springer-Verlag.
BibTeX:
@article{CsizmadiaHarrisonSutcliffe1966,
  author = {Csizmadia, I.G. and Harrison, M.C. and Sutcliffe, B.T.},
  title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part II. Preliminary investigations on formyl fluoride},
  journal = {Theoretica Chimica Acta},
  year = {1966},
  volume = {6},
  pages = {217-239},
  doi = {10.1007/BF02394699}
}
Abstract: Non-empirical molecular quantum chemical calculations were performed on formyl fluoride (HCOF) in the LCAO-MO-SCF framework using Gaussian type functions as atomic orbitals. In the first half of this paper a quantitative correlation has been established between some of the calculable molecular properties of HCOF and the size of the basis set used. It is hoped that the basic conclusions are general enough to be applicable to calculations of similar type on different molecules. The second part consists of a preliminary SCF study of HCOF in its electronic ground state. © 1966 Springer-Verlag.
BibTeX:
@article{CsizmadiaHarrisonSutcliffe1966a,
  author = {Csizmadia, I.G. and Harrison, M.C. and Sutcliffe, B.T.},
  title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part II. Preliminary investigations on formyl fluoride},
  journal = {Theoretica Chimica Acta},
  year = {1966},
  volume = {6},
  pages = {217-239},
  doi = {10.1007/BF02584203}
}
Abstract: An extension of the multiconfigurational SCF approach for the resolution of the vibrational problem is presented; it follows the philosophy of the CASSCF method developed in Quantum Chemistry. The new method allows a more complete treatment of anharmonic mode couplings, converges much faster and gives a clearer physical insight of vibrational interactions. This is exemplified by the calculation of infrared transition moments in the H2O and D2O isotopomers of the water molecule. It is shown how this property varies with the quality of the wave function when vibrational resonances occur. A detailed analysis by means of this new VCASSCF method demonstrates the crucial importance of excited bending oscillators in the intensity of some pure stretching transitions. © 1995 Springer-Verlag.
BibTeX:
@article{CulotLaruelleLievin1995,
  author = {Culot, F. and Laruelle, F. and Liévin, J.},
  title = {A vibrational CASSCF study of stretch-bend interactions and their influence on infrared intensities in the water molecule},
  journal = {Theoretica Chimica Acta},
  year = {1995},
  volume = {92},
  pages = {211-226},
  doi = {10.1007/BF01125947}
}
Abstract: This paper is the second part of a series devoted to the ab initio calculation of vibrational properties, like transition energies, dipole moment matrix elements and infrared intensities.The method of calculation has been detailed in the first paper, where test calculations on diatomic systems were also analyzed.The present paper applies the method to a simple polyatomic system, the water molecule in its ground electronic state.The purely polyatomic features of the method are discussed, as the determination of the potential energy and dipole moment surfaces and the description of vibrational mode couplings.The results concern vibrational energies of levels in the range 0 &lt; v1+ v2+ v3&lt; 3 and vibrational transition moments and intensities of cold and hot bands.Many methodological tests and comparisons to the experimental and theoretical literature are reported, showing that theoretical values of transition energies and dipole moments converge to the experimental ones; at the highest level of approximation (TZ + 2P/SD-CI; vibrational SCF/CI and FCI) the precision obtained is sufficient to provide useful complementary spectroscopical data.This convergence is however not achieved for diagonal dipole moment matrix elements, which are shown to be very sensitive to the mechanical and electrical anharmonicities. © 1992 IOP Publishing Ltd.
BibTeX:
@article{CulotLievin1992,
  author = {Culot, F. and Lievin, J.},
  title = {Ab initio calculation of vibrational dipole moment matrix elements.Ii.the water molecule as a polyatomic test case},
  journal = {Physica Scripta},
  year = {1992},
  volume = {46},
  pages = {502-517},
  doi = {10.1088/0031-8949/46/6/004}
}
Abstract: A new variational method for solving the molecular vibration problem is proposed. The so-called VMCSCF method (vibrational multiconfigurational self-consistent field) is based on the super-CI algorithm, previously developed in the framework of electronic ab initio calculations. This approach makes direct use of the generalised Brillouin theorem to ensure self-consistency. The method is dedicated to the study of strongly interacting states (vibrational resonances), which are one of the main sources of perturbation in vibrational spectra. The interest of the method to tackle resonance interactions is illustrated by means of test calculations performed on the water and formaldehyde molecules. © 1994 Springer-Verlag.
BibTeX:
@article{CulotLievin1994,
  author = {Culot, F. and Liévin, J.},
  title = {A multiconfigurational SCF computational method for the resolution of the vibrational Schrödinger equation in polyatomic molecules},
  journal = {Theoretica Chimica Acta},
  year = {1994},
  volume = {89},
  pages = {227-250},
  doi = {10.1007/BF01225116}
}
Abstract: The Coulomb three-body problem in Jacobi coordinates was solved by treating the distance of the particles having equal charge as a parameter. This method allows computation of electronic energies with finite nuclear masses while maintaining the notion of a potential energy curve. The rotationless ground-state electronic and the so-called adiabatic Jacobi correction (AJC) energies are presented for H2+, D2+, and H D+ at fixed internuclear separations. The AJCs are defined as the difference between the results obtained from calculations using proper finite and infinite nuclear masses. Except at the united atom limit, the AJCs are smaller than the traditional first-order diagonal Born-Oppenheimer corrections. Expectation values of proton-electron, p-e, and deuteron-electron, d-e, distances for H D+ have been computed as a function of internuclear separation. Similarly to the fully nonadiabatic approach, the present method is able to follow the symmetry breaking in H D+. Exact and approximate analytical and numerical results are given for counterfactual systems as well. In these cases changes are allowed for the values of the electron rest mass or the elementary charge, as well as for the mass or charge of the unique particle (electron). © 2007 American Institute of Physics.
BibTeX:
@article{CzakoCsaszarSzalayEtAl2007,
  author = {Czakó, G. and Császár, A.G. and Szalay, V. and Sutcliffe, B.T.},
  title = {Adiabatic Jacobi corrections for H2+ -like systems},
  journal = {Journal of Chemical Physics},
  year = {2007},
  volume = {126},
  article number = {024102},
  doi = {10.1063/1.2406068}
}
Abstract: A technique has been developed which in principle allows the determination of the full rotational-vibrational eigenspectrum of triatomic molecules by treating the important singularities present in the triatomic rotational-vibrational kinetic energy operator given in Jacobi coordinates and the R1 embedding. The singular term related to the diatom-type coordinate, R1, deemed to be unimportant for spectroscopic applications, is given no special attention. The work extends a previous [J. Chem. Phys., 2005, 122, 024101] vibration-only approach and employs a generalized finite basis representation (GFBR) resulting in a nonsymmetric Hamiltonian matrix [J. Chem. Phys., 2006, 124, 014110]. The basis set to be used is obtained by taking the direct product of a 1-D DVR basis, related to R 1, with a 5-D nondirect-product basis, the latter formed by coupling Bessel-DVR functions depending on the distance-type coordinate causing the singularity, associated Legendre polynomials depending on the Jacobi angle, and rotational functions depending on the three Euler angles. The robust implicitly restarted Arnoldi method within the ARPACK package is used for the determination of a number of eigenvalues of the nonsymmetric Hamiltonian matrix. The suitability of the proposed approach is shown by the determination of the rotational-vibrational energy levels of the ground electronic state of H 3 + somewhat above its barrier to linearity. Convergence of the eigenenergies is checked by an alternative approach, employing a Hamiltonian expressed in Radau coordinates, a standard direct-product basis, and no treatment of the singularities. © the Owner Societies 2007.
BibTeX:
@article{CzakoFurtenbacherBarlettaEtAl2007,
  author = {Czakó, G. and Furtenbacher, T. and Barletta, P. and Császár, A.G. and Szalay, V. and Sutcliffe, B.T.},
  title = {Use of a nondirect-product basis for treating singularities in triatomic rotational-vibrational calculations},
  journal = {Annual Reports on the Progress of Chemistry - Section B},
  year = {2007},
  volume = {103},
  pages = {3407-3415},
  doi = {10.1039/b701911d}
}
Abstract: A technique has been developed which in principle allows the determination of the full rotational-vibrational eigenspectrum of triatomic molecules by treating the important singularities present in the triatomic rotational-vibrational kinetic energy operator given in Jacobi coordinates and the R1 embedding. The singular term related to the diatom-type coordinate, R1, deemed to be unimportant for spectroscopic applications, is given no special attention. The work extends a previous [J. Chem. Phys., 2005, 122, 024101] vibration-only approach and employs a generalized finite basis representation (GFBR) resulting in a nonsymmetric Hamiltonian matrix [J. Chem. Phys., 2006, 124, 014110]. The basis set to be used is obtained by taking the direct product of a 1-D DVR basis, related to R1, with a 5-D nondirect-product basis, the latter formed by coupling Bessel-DVR functions depending on the distance-type coordinate causing the singularity, associated Legendre polynomials depending on the Jacobi angle, and rotational functions depending on the three Euler angles. The robust implicitly restarted Arnoldi method within the ARPACK package is used for the determination of a number of eigenvalues of the nonsymmetric Hamiltonian matrix. The suitability of the proposed approach is shown by the determination of the rotational-vibrational energy levels of the ground electronic state of H3 + somewhat above its barrier to linearity. Convergence of the eigenenergies is checked by an alternative approach, employing a Hamiltonian expressed in Radau coordinates, a standard direct-product basis, and no treatment of the singularities. © the Owner Societies.
BibTeX:
@article{CzakoFurtenbacherBarlettaEtAl2007a,
  author = {Czakó, G. and Furtenbacher, T. and Barletta, P. and Császár, A.G. and Szalay, V. and Sutcliffe, B.T.},
  title = {Use of a nondirect-product basis for treating singularities in triatomic rotational-vibrational calculations},
  journal = {Physical Chemistry Chemical Physics},
  year = {2007},
  volume = {9},
  pages = {3407-3415},
  doi = {10.1039/b701911d}
}
Abstract: The Eyjafjallajökull volcano in Iceland erupted explosively on 14 April 2010, emitting a plume of ash into the atmosphere. The ash was transported from Iceland toward Europe where mostly cloud-free skies allowed ground-based lidars at Chilbolton in England and Leipzig in Germany to estimate the mass concentration in the ash cloud as it passed overhead. The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) has been used to simulate the evolution of the ash cloud from the Eyjafjallajökull volcano during the initial phase of the ash emissions, 14-16 April 2010. NAME captures the timing and sloped structure of the ash layer observed over Leipzig, close to the central axis of the ash cloud. Relatively small errors in the ash cloud position, probably caused by the cumulative effect of errors in the driving meteorology en route, result in a timing error at distances far from the central axis of the ash cloud. Taking the timing error into account, NAME is able to capture the sloped ash layer over the UK. Comparison of the lidar observations and NAME simulations has allowed an estimation of the plume height time series to be made. It is necessary to include in the model input the large variations in plume height in order to accurately predict the ash cloud structure at long range. Quantitative comparison with the mass concentrations at Leipzig and Chilbolton suggest that around 3% of the total emitted mass is transported as far as these sites by small (<100 μm diameter) ash particles. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{DacreGrantHoganEtAl2011,
  author = {Dacre, H.F. and Grant, A.L.M. and Hogan, R.J. and Belcher, S.E. and Thomson, D.J. and Devenish, B.J. and Marenco, F. and Hort, M.C. and Haywood, J.M. and Ansmann, A. and Mattis, I. and Clarisse, L.},
  title = {Evaluating the structure and magnitude of the ash plume during the initial phase of the 2010 Eyjafjallajökull eruption using lidar observations and NAME simulations},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D00U03},
  doi = {10.1029/2011JD015608}
}
Abstract: The angular distributions of electrons ejected from collisionally excited O- ions have been measured in order to test the previous assignments of excited states for this ion. The angular distributions support the interpretation that the two dominant peaks in the electron-energy spectrum represent the autodetachment of the 2p3(2D)3s2 2Do state, decaying to the 3P and 1D states of the oxygen ground-state configuration, with an experimental branching ratio of 1.58±0.08, and not that two different autodetaching states are populated, as previously assumed. Theoretical calculations are in good agreement with the experimental findings. © 1993 The American Physical Society.
BibTeX:
@article{DahlAndersenJodalEtAl1993,
  author = {Dahl, P. and Andersen, T. and Jodal, L. and Kylstra, N.J. and Hansen, J.E. and Vaeck, N.},
  title = {Angular distributions in autodetachment from doubly excited O- states},
  journal = {Physical Review A},
  year = {1993},
  volume = {48},
  pages = {2844-2849},
  doi = {10.1103/PhysRevA.48.2844}
}
Abstract: New measurements of carbon monoxide laser frequencies in the 5. 3 to 7. 2 mu m region have been made using the techniques of infrared grating spectroscopy and heterodyne beat frequency detection. The observations concentrated on the rarer isotopic species **1**3C**1**6O, **1**2C**1**8O, and **1**3C**1**8O, and on the lower frequency region of CO laser oscillation, where less data have previously been available. The new results have been combined with a large amount of previous data in a simultaneous least-squares fit involving all known isotopic species of CO. The resulting parameters are a set of 'reduced' Dunham coefficients and a set of mass-scaling factors which describe how their isotopic variation differs from the simple mass-dependence normally assumed. Laser frequencies calculated from the new Dunham coefficients are improved from those and they should prove useful in spectroscopic applications of the CO laser. Comprehensive tables of Dunham coefficients for all CO isotopes and of calculated laser frequencies for **1**2C**1**6O, **1**3C**1**6O, **1**2C**1**8O, and **1**3C**1**8O are given.
BibTeX:
@article{DaleHermanJohnsEtAl1979,
  author = {Dale, R.M. and Herman, M. and Johns, J.W.C. and McKellar, A.R.W. and Nagler, S. and Strathy, I.K.M.},
  title = {IMPROVED LASER FREQUENCIES AND DUNHAM COEFFICIENTS FOR ISOTOPICALLY SUBSTITUTED CARBON MONOXIDE.},
  journal = {Can J Phys},
  year = {1979},
  volume = {57},
  pages = {677-686},
  doi = {10.1139/p79-096}
}
Abstract: Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (&lt;i&gt;N&lt;/i&gt;obs Combining double low line 547) give a mean relative difference of ĝ'32.4ĝ€±ĝ€(56.3)ĝ€%, a correlation &lt;i&gt;r&lt;/i&gt; of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100%). © Author(s) 2016.
BibTeX:
@article{DammersPalmVanDammeEtAl2016,
  author = {Dammers, E. and Palm, M. and Van Damme, M. and Vigouroux, C. and Smale, D. and Conway, S. and Toon, G.C. and Jones, N. and Nussbaumer, E. and Warneke, T. and Petri, C. and Clarisse, L. and Clerbaux, C. and Hermans, C. and Lutsch, E. and Strong, K. and Hannigan, J.W. and Nakajima, H. and Morino, I. and Herrera, B. and Stremme, W. and Grutter, M. and Schaap, M. and Kruit, R.J.W. and Notholt, J. and Coheur, P.-F. and Erisman, J.W.},
  title = {An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10351-10368},
  doi = {10.5194/acp-16-10351-2016}
}
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reúnion (20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging 3 orders of magnitude were obtained, with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) and lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient, as two layers can be distinguished. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations, only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (number of spectra (N)= 554), 30 % for all spectra from Lauder (N = 2412), 25 % for spectra from Reúnion (N = 1262) and 34 % for spectra measured at Jungfraujoch (N = 2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station-specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR instruments provides a new way of obtaining highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © 2015 Author(s).
BibTeX:
@article{DammersVigourouxPalmEtAl2015,
  author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.},
  title = {Retrieval of ammonia from ground-based FTIR solar spectra},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12789-12803},
  doi = {10.5194/acp-15-12789-2015}
}
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier Transform InfraRed (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reunion (20.9° S, 55.50 ° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging three orders of magnitude were obtained with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) to the lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient as two layers can be discriminated. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (Number of spectra (N) Combining double low line 554), 30 % for all spectra from Lauder (N Combining double low line2412), 25 % for spectra from Reunion (N Combining double low line1262) and 34 % for spectra measured at Jungfraujoch (N Combining double low line2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR-instruments provides a new way to obtain highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © Author(s) 2015.
BibTeX:
@article{DammersVigourouxPalmEtAl2015a,
  author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.},
  title = {Retrieval of ammonia from ground-based FTIR solar spectra},
  journal = {Atmospheric Chemistry and Physics Discussions},
  year = {2015},
  volume = {15},
  pages = {23279-23315},
  doi = {10.5194/acpd-15-23279-2015}
}
Abstract: High resolution Fourier transform spectra of the 21102-00001 band of 12C16O2 near 3340cm-1 have been recorded and analyzed to extract isolated-line intensities and collisional parameters, and first-order line-mixing coefficients. Voigt, hard-collision Rautian and Sobel'man, and quadratic-speed-dependent Voigt profiles have been used. The line-mixing coefficients measured for the three branches have also been evaluated using an Energy-Corrected Sudden approach employing a symmetric metric in the Liouville space. These coefficients compare very favorably with the experimental results and estimations with an algorithm available in the literature. Results of straightforward ECS-modeling of complete band shapes have been compared to the recorded spectra and future improvements of this model required at subatmospheric pressures have been outlined. © 2014 Elsevier Ltd.
BibTeX:
@article{DaneshvarFoeldesBuldyrevaEtAl2014,
  author = {Daneshvar, L. and Földes, T. and Buldyreva, J. and Auwera, J.V.},
  title = {Infrared absorption by pure CO2 near 3340cm-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {149},
  pages = {258-274},
  doi = {10.1016/j.jqsrt.2014.08.007}
}
Abstract: I-V modelling of heterojunctions taking into account the heterointerface parameters is used to establish an analytical model of collector/emitter offset voltage in Heterojunction Bipolar Transistors. It is shown that careful design of Emitter Base (E-B) and Collector Base (C-B) interfaces can eliminate this problem. Comparisons with experimental results obtained with MBE and MOCVD grown transistors are presented. © 1985.
BibTeX:
@article{DanglaCaquotDubonEtAl1985,
  author = {Dangla, J. and Caquot, E. and Dubon, C. and Campana, M. and Azoulay, R. and Alexandre, F. and Lievin, J. and Palmier, J.F. and Ankri, D.},
  title = {Modelling of d.c. characteristics of heterojunction bipolar transistor processed with MBE or MOCVD techniques},
  journal = {Physica B+C},
  year = {1985},
  volume = {129},
  pages = {366-370},
  doi = {10.1016/0378-4363(85)90603-5}
}
Abstract: I-V modeling of heterojunctions taking into account the heterointerface parameters is used to establish an analytical model of collector/emitter offset voltage in Heterojunction Bipolar Transistors. It is shown that careful design of Emitter Base (E-B) and Collector Base (C-B) interfaces can eliminate this problem. Comparisons with experimental results obtained with MBE and MOCVD grown transistors are presented.
BibTeX:
@article{DanglaCaquotDubonEtAl1984,
  author = {Dangla, J. and Caquot, E. and Dubon, C. and Campana, M. and Azoulay, R. and Alexandre, F. and Lievin, J. and Palmier, J.F. and Ankri, D.},
  title = {MODELLING OF D. C. CHARACTERISTICS OF HETEROJUNCTION BIPOLAR TRANSISTOR PROCESSED WITH MBE OR MOCVD TECHNIQUES.},
  journal = {Physica B: Physics of Condensed Matter & C: Atomic, Molecular and Plasma Physics, Optics},
  year = {1984},
  volume = {129 B-C},
  pages = {366-370}
}
Abstract: High-resolution water vapor absorption spectra have been measured at room temperature in the 8800-11,600cm -1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600m and different H 2O/HDO/D 2O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD 16O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν 3, 2ν 1+ν 3, 3ν 1+ν 2, ν 1+2ν 3 and 2ν 2+2ν 3 are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications. © 2012 Elsevier Ltd.
BibTeX:
@article{DaumontJenouvrierMikhailenkoEtAl2012,
  author = {Daumont, L. and Jenouvrier, A. and Mikhailenko, S. and Carleer, M. and Hermans, C. and Fally, S. and Vandaele, A.C.},
  title = {High resolution Fourier transform spectroscopy of HD 16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600cm -1 spectral region},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {878-888},
  doi = {10.1016/j.jqsrt.2012.02.017}
}
Abstract: The absorption spectrum of N2O, at room temperature, was recorded in the 5400-11 000 cm-1 region at resolutions ranging from 0.008 cm-1 near 5400 to 0.023 cm-1 near 11 000 cm-1 using a Bruker IFS120HR Fourier transform spectrometer. Sample pressure/absorption path length products ranging from 200 to 4700 mbar×m were used. More than 6000 absolute line intensities have been measured in 64 different bands of 14N216O. Using wavefunctions previously determined from a global fit of an effective Hamiltonian to more than 18 000 line positions [Tashkun SA, Perevalov VI, and Teffo JL, to be published], the experimental intensities measured in this work and by Toth [J Mol Spectrosc 1999;197:158-87] were fit using 62 parameters of a corresponding effective dipole moment, with residuals very close to the experimental uncertainty. © 2006 Elsevier Ltd. All rights reserved.
BibTeX:
@article{DaumontVanderAuweraTeffoEtAl2007,
  author = {Daumont, L. and Vander Auwera, J. and Teffo, J.-L. and Perevalov, V.I. and Tashkun, S.A.},
  title = {Line intensity measurements in 14N216O and their treatment using the effective dipole moment approach.II. The 5400-11 000 cm-1 region},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2007},
  volume = {104},
  pages = {342-356},
  doi = {10.1016/j.jqsrt.2006.09.004}
}
Abstract: This work continues a series of publications devoted to the application of the effective operator approach to the vibrational-rotational treatment of linear triatomic molecules, aiming at the analysis and prediction of their infrared spectra. In that frame work, we have started a large-scale work aiming at the global description of line intensities of cold and hot bands of 14N2 16O in its ground electronic state in the spectral range above 3600 cm−1. In 14N2 16O, vibrational interacting levels group in polyads as a result of the relation 2ω1 ≈ 4ω2 ≈ ω3 existing between the harmonic frequencies. The polyads are identified by the so-called polyad number P = 2V1 + V2 + 4V3. The work described in the present paper concerns bands associated with transitions corresponding to ΔP = 7, 8, and 9. The absorption spectra of N2O at room temperature have been recorded at a resolution of 0.007 cm−1 in the range from 4300 to 5200 cm−1 using a Bruker IFS120HR Fourier transform spectrometer. Sample pressure/absorption path length products ranging from 7 to 1753 mbar x m have been used. More than 3000 absolute line intensities have been measured in 66 different bands belonging to the ΔP = 7, 8, and 9 series. Dicke narrowing has been observed in the high-pressure spectra. Using wavefunctions previously determined from a global fit of an effective Hamiltonian to about 18, 000 line positions (S. A. Tashkun, V. I. Perevalov, and J.-L. Teffo to be published), the experimental intensities measured in this work and by R. A. Toth (J. Mol. Spectrosc. 197, 158-187 (1999)) were fitted to 47 parameters of a corresponding effective dipole moment, with residuals very close to the experimental uncertainty. Examples are given showing that the modeling reproduces intensities of perturbed lines well. © 2001 Academic Press.
BibTeX:
@article{DaumontVanderAuweraTeffoEtAl2001,
  author = {Daumont, L. and Vander Auwera, J. and Teffo, J.-L. and Perevalov, V.I. and Tashkun, S.A.},
  title = {Line intensity measurements in 14N2 16O and their treatment using the effective dipole moment approach: I. The 4300- to 5200-cm−1 Region},
  journal = {Journal of Molecular Spectroscopy},
  year = {2001},
  volume = {208},
  pages = {281-291},
  doi = {10.1006/jmsp.2001.8400}
}
Abstract: Proofs of principle spectra of C2H4, N2O and C2H2, including H12C13CH in natural abundance, are reported, recorded in the 1.6 mm range in an Ar supersonic expansion using femto-Fourier transform-cavity enhanced absorption spectroscopy. The effective absorption pathlength in the jet-cooled sample is up to 78m and the optimal S/N is over 2300. The data processing is detailed. Saturation effects are reported for the C2H2 bands. spectroscopy © 2012 Taylor and Francis.
BibTeX:
@article{DeGhellinckDElseghemVaernewijckGolebiowskiHerman2012,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Golebiowski, D. and Herman, M.},
  title = {Femto-Fourier transform-cavity enhanced absorption spectroscopy in a supersonic expansion},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2735-2741},
  doi = {10.1080/00268976.2012.701342}
}
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a highresolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing an optimal rms noise equivalent absorption of 1.2×10-10 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin=10-8 cm-1. Spectra were calibrated against acetylene reference line positions. Three bands in the 3v 1+v3 tetrad in both 12C17O 2 and 12C17O18O have been identified and rotationally analyzed, as well as some related hot bands, eight of which are newly reported and three with their analysis updated compared with a preliminary report (X. de Ghellinck d'Elseghem Vaernewijck et al., Chem. Phys. Lett. 514, 29 (2011)). © 2012 Taylor and Francis.
BibTeX:
@article{DeGhellinckDElseghemVaernewijckKassiHerman2012,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.},
  title = {17O12C17O and 18O 12C17O spectroscopy in the 1.6 μm region},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2665-2671},
  doi = {10.1080/00268976.2012.705346}
}
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a high resolution continuous scan Fourier transform interferometer fitted with a femto OPO laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing for an optimal rms noise equivalent absorption of 4.4 × 10-9 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin = 3 × 10-7 cm-1. The 3ν1 + ν3 and related hot bands in 12C17O2 and the 3ν1 + ν3 R-branch in 12C17O18O have been identified and rotationally analyzed. © 2011 Elsevier B.V. All rights reserved.
BibTeX:
@article{DeGhellinckDElseghemVaernewijckKassiHerman2011,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.},
  title = {17O12C17O and 18O 12C17O overtone spectroscopy in the 1.64 μm region},
  journal = {Chemical Physics Letters},
  year = {2011},
  volume = {514},
  pages = {29-31},
  doi = {10.1016/j.cplett.2011.08.025}
}
Abstract: A femto-OPO laser fitted to a high-finesse cavity and a Fourier transform spectrometer to perform femto-FT-CEAS (for femto-Fourier transform-cavity enhanced spectroscopy) was used to record high overtones of carbon disulfide with a minimal rms equivalent absorption coefficient of 1.2 × 10 -11 cm-1 Hz-1/2 per spectral element. New vibrational states are reported for 12C32S2 and 12C32S34S and new or improved rotational constants are obtained, for the v1v2l2v3 = 3003, 2203, 0114 and 4003 states in 12C32S2 and 3003 state in 32S12C34S. © 2012 Elsevier Inc. All rights reserved.
BibTeX:
@article{DeGhellinckDElseghemVaernewijckKongoloTshikalaLepereEtAl2012,
  author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kongolo Tshikala, P. and Lepère, M. and Herman, M.},
  title = {Femto-FT-CEAS applied to carbon disulfide around 1.54 μm},
  journal = {Journal of Molecular Spectroscopy},
  year = {2012},
  volume = {282},
  pages = {27-29},
  doi = {10.1016/j.jms.2012.10.006}
}
Abstract: The 0-0, 1-1, 2-2, and 3-3 bands of the A2Π-X2Σ+ transition of the tritiated beryllium monohydride molecule have been observed at 5000 Å in emission using a beryllium hollow-cathode discharge in a He + T2 mixture. The rotational analysis of these bands yields the following principal molecular constants. A2Π:Be = 4.192 cm-1; re = 1.333 A ̊X2Σ:Be = 4.142 cm-1; re = 1.341 A ̊ωe′ - ωe″ = 16.36 cm-1; ωe′Xe′ - ωe″Xe″ = 0.84 cm-1. From the pure electronic energy difference (EΠ - EΣ)BeT = 20 037.91 ± 1.5 cm-1 and the corresponding previously known values for BeH and BeD, the following electronic isotope shifts are derived ΔEei(BeH-BeT) = -4.7 ≠ 1.5cm1, ΔEei(BeH-BeT) = -1.8 ≠ 1.5cm1 and related to the theoretical approach given by Bunker to the problem of the breakdown of the Born-Oppenheimer approximation. © 1994.
BibTeX:
@article{DeGreefColin1974,
  author = {De Greef, D. and Colin, R.},
  title = {The electronic isotope shift in the A2Π-X2Σ+ bands of BeH, BeD and BeT},
  journal = {Journal of Molecular Spectroscopy},
  year = {1974},
  volume = {53},
  pages = {455-465},
  doi = {10.1016/0022-2852(74)90082-4}
}
Abstract: The Double Focusing Mass Spectrometer (DFMS), part of the ROSINA instrument package aboard the European Space Agency's Rosetta spacecraft visiting comet 67P/Churyumov-Gerasimenko, experiences minor deformation of the mass peaks in the high resolution spectra acquired for m/Z = 16, 17, and to a lesser extent 18. A numerical deconvolution technique has been developed with a twofold purpose. A first goal is to verify whether the most likely cause of the issue, a lack of stability of one of the electric potentials in the electrostatic analyser, can indeed be held responsible for it. The second goal is to correct for the deformation, in view of the important species located around these masses, and to allow a standard further treatment of the spectra in the automated DFMS data processing chain. © 2015 The Authors. Published by Elsevier B.V.
BibTeX:
@article{DeKeyserDhoogheGibbonsEtAl2015,
  author = {De Keyser, J. and Dhooghe, F. and Gibbons, A. and Altwegg, K. and Balsiger, H. and Berthelier, J.-J. and Briois, C. and Calmonte, U. and Cessateur, G. and Equeter, E. and Fiethe, B. and Fuselier, S.A. and Gombosi, T.I. and Gunell, H. and Hässig, M. and Le Roy, L. and Maggiolo, R. and Neefs, E. and Rubin, M. and Sémon, T.},
  title = {Correcting peak deformation in Rosetta's ROSINA/DFMS mass spectrometer},
  journal = {International Journal of Mass Spectrometry},
  year = {2015},
  volume = {393},
  pages = {41-51},
  doi = {10.1016/j.ijms.2015.10.010}
}
Abstract: The experimental vibrational frequencies of s-trans-1,3-butadiene, for which the assignments are well-established, are used to determine the scale factors for its quantum mechanical force field obtained at the MP2/6-31G*//MP2/6-31G* level of theory. The scale factors are then transferred to the MP2/6-31G*//MP2/ 6-31G* force fields of the s-cis and s-gauche rotamers and their theoretical frequencies calculated. Comparison of the vibrational frequencies of these three species indicates a special region of the IR spectrum of 1,3-butadiene in the gas phase (720-790 cm-1) in which only a band attributable to the s-gauche rotamer should be present; i.e., it should be free both of the observed IR bands of the s-trans and of the calculated vibrational frequencies of the s-cis conformer. Investigation of the medium- and high-resolution IR spectra of 1,3-butadiene in the gas phase reveals the presence of a band at 749.22(20) cm-1 possessing the typical B contour (consistent with A symmetry, C2 group). Rotational analysis of the medium-resolution spectrum of this band yields the rotational constants A″ - B″ = 0.4478(27) cm-1 and A′ - B̄′ = 0.4455(25) cm1, only about one-third of the experimental values for s-trans-1,3-butadiene. This identifies the band as belonging to the high-energy conformer of 1,3-butadiene. The agreement between the experimental and theoretical values of the band center (749 vs 735 cm-1), the clear B type contour, and the extremely complicated character of the high-resolution spectrum of the band at 749.22 cm-1 strongly suggest that the geometry of the high-energy conformer of 1,3-butadiene in the gas phase is nonplanar s-gauche and not planar s-cis.
BibTeX:
@article{DeMarePanchenkoAuwera1997,
  author = {De Maré, G.R. and Panchenko, Y.N. and Auwera, J.V.},
  title = {Structure of the high-energy conformer of 1,3-butadiene},
  journal = {Journal of Physical Chemistry A},
  year = {1997},
  volume = {101},
  pages = {3998-4004},
  doi = {10.1021/jp970478y}
}
BibTeX:
@article{DeNataleDiLonardoHermanEtAl2010,
  author = {De Natale, P. and Di Lonardo, G. and Herman, M. and Quack, M. and Softley, T.},
  title = {Foreword: Twenty-first colloquium on high-resolution molecular spectroscopy},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {675-676},
  doi = {10.1080/00268971003798187}
}
Abstract: The IASI (Infrared Atmospheric Sounding Interferometer) nadir-looking thermal infrared sounder onboard MetOp-A enables the monitoring of atmospheric constituents on a global scale. This paper presents a quality assessment of IASI CO profiles retrieved by the two different retrieval algorithms SOFRID and FORLI, by an intercomparison with airborne in-situ CO profiles from the MOZAIC program for the 2008-2009 period. Lower (surface-480 hPa) and upper tropospheric partial column (480-225 hPa) comparisons as well as profile comparisons are made. The retrieval errors of the IASI products are less than 21% in the lower troposphere and less than 10% in the upper troposphere. A statistical analysis shows similar correlation coefficients for the two retrieval algorithms and smoothed MOZAIC of r ∼ 0.8 and r ∼ 0.7 in the lower and upper troposphere respectively. Comparison with smoothed MOZAIC data of the temporal variation of the CO profiles at the airports of Frankfurt and Windhoek demonstrates that the IASI products are able to capture the seasonal variability at these sites. At Frankfurt SOFRID (respectively FORLI) is positively biased by 10.5% (13.0%) compared to smoothed MOZAIC in the upper (lower) troposphere, and the limited sensitivity of the IASI instrument to the boundary layer when thermal contrast is low is identified. At Windhoek, the impact of the vegetation fires in Southern Africa from July to November is captured by both SOFRID and FORLI, with an overestimation of the CO background values (fire maxima) by SOFRID (FORLI) by 12.8% (10%). Profile comparisons at Frankfurt and Windhoek show that the largest discrepancies are found between the two IASI products and MOZAIC for the nighttime retrievals. © 2012 Author(s).
BibTeX:
@article{DeWachterBarretLeFlochmoenEtAl2012,
  author = {De Wachter, E. and Barret, B. and Le Flochmoën, E. and Pavelin, E. and Matricardi, M. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Hurtmans, D. and Coheur, P.-F. and Nedelec, P. and Cammas, J.P.},
  title = {Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {2843-2857},
  doi = {10.5194/amt-5-2843-2012}
}
Abstract: The equilibrium structure of 36 small molecules containing OH bonds, including molecules with an internal hydrogen bond, is reviewed from the literature. The structures are redetermined or determined, if necessary, using high level ab initio calculations at the CCSD(T) level of theory with basis sets of quintuple zeta quality and with a correction for the core correlation. The possibility of calculating accurate ab initio OH bond lengths at different levels of theory (MP2/VTZ, MP2/VQZ, CCSD(T)/VTZ, and CCSD(T)/AVTZ) is examined. All methods agree provided a small offset correction is taken into account. In most cases, the addition of diffuse functions does not improve the results. The MP2 method appears to be satisfactory whenever the non-dynamical electron correlation is small, which is the most typical situation. The various results are merged to demonstrate the following quantitative correlation between re(OH) and 'isolated' OH stretching frequencies, relevant for predictive use: re(OH) [Å] = 1.2261(76)-7.29(21) x 10-5 νis(OH) [cm-1]. © 2007 Taylor & Francis.
BibTeX:
@article{DemaisonHermanLievin2007,
  author = {Demaison, J. and Herman, M. and Lievin, J.},
  title = {The equilibrium OH bond length},
  journal = {International Reviews in Physical Chemistry},
  year = {2007},
  volume = {26},
  pages = {391-420},
  doi = {10.1080/01442350701371919}
}
Abstract: The rotational spectra of the ground vibrational state and the ν9 = 1 torsional state have been reinvestigated and accurate spectroscopic constants have been determined. The torsional frequency, ν9 = 70(15) cm-1, has been determined by relative intensity measurements. The assignment of the infrared spectrum has been slightly revised and an accurate harmonic force field has been calculated. The equilibrium structure has been determined using different, complementary methods: experimental, semi-experimental and ab initio, leading to r(NN) = 1.870(2) Å, in particular. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{DemaisonHermanLievinEtAl2007a,
  author = {Demaison, J. and Herman, M. and Liévin, J. and Margulès, L. and Møllendal, H.},
  title = {Rotational spectrum and structure of asymmetric dinitrogen trioxide, N2O3},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {244},
  pages = {160-169},
  doi = {10.1016/j.jms.2007.06.003}
}
Abstract: The equilibrium structure of the more stable conformer of H 2SO4, of C2 symmetry, has been calculated ab initio using the CCSD(T) method and taking into account the core correlation correction. The accuracy of this structure has been checked by comparing it to that of similar molecules and by estimating the effects of basis set enlargement and of diffuse functions. Furthermore, the quadratic, cubic, and quartic force fields have been calculated at the MP2 level of theory using a basis set of triple-ζ quality. The spectroscopic constants derived from the force field are in satisfactory agreement with the experimental ones. The resulting band origins are compared to literature infrared values, including those for overtone and combination bands. Normal modes of vibration are pictured. Using this force field, semiexperimental equilibrium rotational constants are determined which allows us to check the accuracy of the ab initio structure and to refine it using a mixed regression method. © 2007 American Chemical Society.
BibTeX:
@article{DemaisonHermanLievinEtAl2007,
  author = {Demaison, J. and Herman, M. and Liévin, J. and Rudolph, H.D.},
  title = {Equilibrium structure of sulfuric acid},
  journal = {Journal of Physical Chemistry A},
  year = {2007},
  volume = {111},
  pages = {2602-2609},
  doi = {10.1021/jp068808e}
}
Abstract: The quadratic, cubic, and semidiagonal quartic force fields of cis- and trans-formic acid have been calculated using three different levels of theory. They all give satisfactory results, including the one at the lowest level of theory which is the MP2 method employing a basis set of triple- quality. The results are used to theoretically analyze resonance polyads, including the one involving the 41, 51, 61, 81, 71 91, and 92 vibrational states. A semiexperimental equilibrium structure is derived from experimental ground state rotational constants and rovibrational interaction parameters calculated from the ab initio force field. The ab initio structure calculated at the CCSD(T) level of theory using a basis set of quintuple- quality is in excellent agreement with the semiexperimental structure. © 2007 American Institute of Physics.
BibTeX:
@article{DemaisonHermanLivin2007,
  author = {Demaison, J. and Herman, M. and Lívin, J.},
  title = {Anharmonic force field of cis- and trans-formic acid from high-level ab initio calculations, and analysis of resonance polyads},
  journal = {Journal of Chemical Physics},
  year = {2007},
  volume = {126},
  article number = {164305},
  doi = {10.1063/1.2722752}
}
Abstract: The equilibrium structure of the hydrogen bonded complex H2O HF has been calculated ab initio using the CCSD(T) method with basis sets up to sextuple- quality with diffuse functions and taking into account the basis set superposition error correction. The calculations carried out confirm the importance of diffuse functions and of counterpoise correction to obtain an accurate geometry. The most important point is that the basis set convergence is extremely slow and, for this reason an accurate ab initio structure requires a very large basis set. Nevertheless, the ab initio structure is significantly different from the experimental r0 and rm structures. Analysis of the basis set convergence and of the approximations used for the determination of the experimental structures indicates that the ab initio structure is expected to be more reliable.
BibTeX:
@article{DemaisonLievin2008,
  author = {Demaison, J. and Lievin, J.},
  title = {Equilibrium structure of the hydrogen bonded dimer H2O ⋯ HF},
  journal = {Molecular Physics},
  year = {2008},
  volume = {106},
  pages = {1249-1256},
  doi = {10.1080/00268970802139908}
}
Abstract: Born-Oppenheimer equilibrium structures, reBO, of the electronic ground state of the borazane (BH3NH3) molecule of C3v., point-group symmetry are computed ab initio using the CCSD(T) method with basis sets up to quintuple-ζ quality. Inclusion of the counterpoise correction and extrapolation of the structural parameters to the complete basis set limit yield a best estimate of reBO of BH3NH3. The anharmonic force field of BH 3NH3, computed at the CCSD(T) level of theory with a basis set of triple-ζ quality, allows the determination of semi-experimental equilibrium rotational constants, which in turn result in a semi-experimental equilibrium structure, reSE. The re BO and reSE structures are in excellent agreement, indicating the validity of the methods used for their determination. The empirical mass-dependent structure, rm(1), of BH 3NH3 is also determined. Although it is inferior in quality to the previous two structures, it is much more accurate than the standard empirical r0 and rs structures reported earlier for BH3NH3. The semi-experimental re SE as well as the empirical rm(1) structures determined are based on experimental ground-state rotational constants available from the literature for nine isotopologues of borazane. The effective barrier to the internal rotation of BH3NH3, a molecule isoelectronic with CH3CH3, has been computed ab initio, employing the focal-point analysis (FPA) approach, to be 699 ±11 cm -1. This compares favorably with an empirical redetermination of the effective barrier based on the above reSE structure, V3 = 718(17) cm-1. © 2008 American Chemical Society.
BibTeX:
@article{DemaisonLievinCsaszarEtAl2008,
  author = {Demaison, J. and Liévin, J. and Császár, A.G. and Gutle, C.},
  title = {Equilibrium structure and torsional barrier of BH3NH3},
  journal = {Journal of Physical Chemistry A},
  year = {2008},
  volume = {112},
  pages = {4477-4482},
  doi = {10.1021/jp710630j}
}
Abstract: We investigate the stability of homonuclear diatomic molecules from H2 up to C2 and of the finite chains Hn (n≤5) and Hen (n≤4) immersed in very intense magnetic fields (B108 T). The atomic and molecular total energies are calculated within the one-dimensional Hartree-Fock approximation, using a Lagrange basis set associated with a Cartesian mesh. The stability of the molecules decreases beyond Li2 although all the studied molecules are found stable. The energy per atom of H and He finite chains stabilizes already for the small chain sizes that we have investigated. © 1994 The American Physical Society.
BibTeX:
@article{DemeurHeenenGodefroid1994,
  author = {Demeur, M. and Heenen, P.-H. and Godefroid, M.},
  title = {Hartree-Fock study of molecules in very intense magnetic fields},
  journal = {Physical Review A},
  year = {1994},
  volume = {49},
  pages = {176-183},
  doi = {10.1103/PhysRevA.49.176}
}
Abstract: Fourier-transform intracavity laser absorption spectroscopy allowed five 12C13CH2Σ+- Σ+ bands, all from the ground state, to be identified in the 0.83 μm range. Their rotational analysis was performed and rotational constants are provided. Three of these bands, with origins at 11616.9684(18), 11737.2356(14), and 11761.0322(23) cm-1, have never been reported before. Their upper states are assigned to V1V2V 3v4 l4v5 l5 = 1302 020, 130113-1, and 22011 1-1, respectively. © 2004 Elsevier Inc. All rights reserved.
BibTeX:
@article{DepiesseDiLonardoFaytEtAl2005,
  author = {Depiesse, C. and Di Lonardo, G. and Fayt, A. and Fusina, L. and Hurtmans, D. and Robert, S. and Tamassia, F. and Vander Auwera, J. and Baldan, A. and Herman, M.},
  title = {New combination bands in12C13CH2 around 0.83 μm recorded using FT-ICLAS},
  journal = {Journal of Molecular Spectroscopy},
  year = {2005},
  volume = {229},
  pages = {137-139},
  doi = {10.1016/j.jms.2004.08.006}
}
Abstract: Relativistic energies are computed for a series of j states corresponding to 1s22sm2pn (0?m?2; 0?n?6) configurations by solution of the hartree-fock-dirac equations. The j states calculated are those states whose eigenfunctions within a configuration correspond to a unique and maximum eigenvalue of the operator j2. In addition, average relativistic energies are obtained for all configurations considered. The two sets of results are compared, and in certain cases (for the 1s22p, 1s22p5, 1s22s22p, 1s 22s22p5 configurations) permit a determination of multiplet splittings (e(2p12/-2p 32/)). The results of these splittings are in excellent agreement with available experimental data. The present results also tend to confirm the assumption that the relativistic energy contributions for the j averaged ls states are the same for all states arising from the same configuration. This makes it possible to evaluate the relativistic energies of all states belonging to the configurations of interest to this paper. These in turn serve to re-evaluate more correctly recently obtained correlation energies for the same states.
BibTeX:
@article{DesclauxMoserVerhaegen1971,
  author = {Desclaux, J.P. and Moser, C.M. and Verhaegen, G.},
  title = {Relativistic energies of excited states of atoms and ions of the second period},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1971},
  volume = {4},
  article number = {003},
  pages = {296-310},
  doi = {10.1088/0022-3700/4/3/003}
}
Abstract: Non-Hermitian complex effective Hamiltonians resulting from bound-continuous partitioning techniques are built from time dependent methods. We treat predissociation processes with a curve crossing. The energy dependent shift and half-width matrices are obtained simultaneously by a generalization of the wave packet Golden Rule treatment, as the real and imaginary parts of the Fourier transform of a memory kernel matrix. The latter contains auto- and cross-correlation functions. They are overlap integrals among the projections on the continuum of bound states multiplied by the interchannel coupling function responsible for the predissociation. These wave packets are propagated by the propagator of the sole continuous subspace. An approximate analytical expression of this correlation matrix is established for the harmonic/linear model. The numerical method is applied to the electronic predissociation of the MgCl A 2Π state, to a Morse/ exponential model and to a predissociation with two coupled repulsive decay channels. The comparison between the correlation time scales and the Golden Rule lifetimes is decisive so as to justify whether the memory kernel can be considered as an impulsive kernel. This Markovian approximation implies that the two time scales are well separated. In the energy domain, this corresponds to the introduction of a mean phenomenological effective Hamiltonian that neglects the energy variation of the discrete-continuous coupling elements. We observe that the separation of the time scales is effective for weakly open systems, but not for overlapping metastable states for which the perturbative-theory widths largely exceed the mean energy spacing. This confirms from a temporal viewpoint that a nonperturbative treatment should not neglect the energy dependence of the effective Hamiltonian, as currently assumed in the study of largely open systems. © 1997 American Institute of Physics.
BibTeX:
@article{Desouter-LecomteLievin1997,
  author = {Desouter-Lecomte, M. and Liévin, J.},
  title = {Memory kernels and effective Hamiltonians from time dependent methods. I. Predissociation with a curve crossing},
  journal = {Journal of Chemical Physics},
  year = {1997},
  volume = {107},
  pages = {1428-1440},
  doi = {10.1063/1.474497}
}
Abstract: The interaction of overlapping resonances is studied in the case of a vibrational predissociation in a linear molecule. The energy independent approach rests on the neglect of the variation of the coupling elements with the energy in the continuum. It predicts the formation of trapped and short-lived decay modes when resonances overlap. The relevance of this prediction is discussed on the basis of results obtained from two different methods going beyond this energy independent formalism. The first one consists in searching the solutions of the implicit equation derived from the Feshbach partitioning method, taking into account the full energy dependence of the local effective Hamiltonian Heff(E). The second one is the variational complex coordinate method (CCM), implemented in a discrete variable representation (DVR). The results demonstrate that the energy dependency enhances the trapping effect. The distribution of the resonance energies in the complex plane is different from the prediction of the energy independent formalism. The fast modes are found to be slower than expected. Their position is also completely shifted. The mean width is not constrained by a sum rule which is characteristic of the energy independent approximation. © 1995 American Institute of Physics.
BibTeX:
@article{Desouter-LecomteLievinBrems1995,
  author = {Desouter-Lecomte, M. and Liévin, J. and Brems, V.},
  title = {Avoided resonance overlapping beyond the energy independent formalism. I. Vibrational predissociation},
  journal = {The Journal of Chemical Physics},
  year = {1995},
  volume = {103},
  pages = {4524-4537},
  doi = {10.1063/1.470641}
}
Abstract: Building upon previous studies, we re-investigated the ethane spectrum between 1330 and 1610 cm -1 by combining unapodized spectra obtained at room temperature with a Bruker Fourier transform spectrometer (FTS) in Brussels and at 131 K with a Bruker FTS in Pasadena. The maximum optical path differences (MOPD) of the two datasets were 450 and 323.7 cm, corresponding to spectral resolutions of 0.0020 and 0.0028 cm -1, respectively. Of the 15,000 lines observed, over 4592 transitions were assigned to the ν 6 (at 1379 cm -1), ν 8 (at 1472 cm -1), ν 4ν 12 (at 1481 cm -1) and 2ν 4ν 9 (at 1388 cm -1) bands, and another 1044 transitions were located for the ν 4ν 8- ν 4 hot band (at 1472 cm -1). Our new analysis included an improved implementation of the Hamiltonian calculation needed to interpret the complex spectral structures caused by numerous interactions affecting these four modes of vibration. From these results, we created the first line-by-line database containing the molecular parameters for over 20,000 12C 2H 6 transitions at 7 μm. © 2011 Elsevier Ltd. All rights reserved.
BibTeX:
@article{DiLauroLattanziBrownEtAl2012,
  author = {Di Lauro, C. and Lattanzi, F. and Brown, L.R. and Sung, K. and Vander Auwera, J. and Mantz, A.W. and Smith, M.A.H.},
  title = {High resolution investigation of the 7 μm region of the ethane spectrum},
  journal = {Planetary and Space Science},
  year = {2012},
  volume = {60},
  pages = {93-101},
  doi = {10.1016/j.pss.2011.01.008}
}
Abstract: Forty cold bands and 29 hot bands are reported from the high resolution Fourier transform (FT) absorption spectrum of 13CH12CH, all leading to vibrational states located between 6750 and 9500 cm-1. Each of these bands has been vibrationally assigned and rotationally analysed. The band centres (νc), vibrational term values (Gv) and rotational constants are listed.
BibTeX:
@article{DiLonardoFusinaTamassiaEtAl2008,
  author = {Di Lonardo, G. and Fusina, L. and Tamassia, F. and Fayt, A. and Robert, S. and Auwera, J.V. and Herman, M.},
  title = {The FT absorption spectrum of 13CH12CH (III): Vibrational states in the range 6750 to 9500 cm-1},
  journal = {Molecular Physics},
  year = {2008},
  volume = {106},
  pages = {1161-1169},
  doi = {10.1080/00268970802020348}
}
Abstract: The infrared spectrum of 13CH12CH has been recorded in the 9500–10000 cm−1 wavenumber region by Fourier transform spectroscopy. Twelve Σ+–Σ+ and one ‘perturbation allowed’ Δ–Σ+ cold bands, and four Π–Π hot bands have been identified. All these bands have been rotationally analysed and vibrationally assigned. They mainly involve triple excitations of the CH stretching modes. The relative intensities have been measured. Local interaction patterns are identified and discussed. Line wavenumbers from the two strongest bands observed in the range are listed. © 2006 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{DiLonardoFusinaTamassiaEtAl2006,
  author = {Di Lonardo, G. and Fusina, L. and Tamassia, F. and Fayt, A. and Robert, S. and Vander Auwera, J. and Herman, M.},
  title = {The FT absorption spectrum of 13CH12CH (II): Rotational analysis of the range 9500 to 10000 cm−1},
  journal = {Molecular Physics},
  year = {2006},
  volume = {104},
  pages = {2617-2625},
  doi = {10.1080/00268970600688536}
}
Abstract: A total of 134 vibrational levels with assigned rotational structure have been gathered in the ground electronic state of 13C2H2. Most of these measurements are updated or new compared to the previously published data. Altogether, they cover the range up to 23 670 cm-1. 118 out of the 119 levels observed below 13 000 cm-1 have been simultaneously fitted using the so-called cluster model, already used to deal with the vibrational energy levels in other isotopomers of acetylene [El Idrissi et al., J. Chem. Phys. 110, 2074 (1999), and references therein]. Twenty-nine vibrational constants have been determined, including the off-diagonal parameters K3/245, K1/244, K1/255, K11/33, K14/35, and r45, with a rms of the fit equal to 0.52 cm-1. The same three constants of the motion as in 12C2H2 emerged, Ns = v1+v2+v3, Nr=5v1+3v2+5v3+v4+v 5 and k=l4+l5. The energies of the levels above 13 000 cm-1 calculated with the obtained parameters compare reasonably well with the experimental values. For all levels the predicted rotational constants compare satisfactorily with the experimental results. © 1999 American Institute of Physics.
BibTeX:
@article{DiLonardoFusinaVenutiEtAl1999,
  author = {Di Lonardo, G. and Fusina, L. and Venuti, E. and Johns, J.W.C. and El Idrissi, M.I. and Liévin, J. and Herman, M.},
  title = {The vibrational energy pattern in acetylene. V. 13C2H2},
  journal = {Journal of Chemical Physics},
  year = {1999},
  volume = {111},
  pages = {1008-1016},
  doi = {10.1063/1.479381}
}
Abstract: Three rovibrational bands of Ar-D2O and two rovibrational bands of Ar-HDO were observed in the 1.5 μm range by continuous wave cavity ringdown spectroscopy. Their analyses led to the determination of rotational constants for the upper states and vibrational shifts indicating that the potential energy surface is only slightly affected by the vibrational excitation. Some Coriolis couplings were identified. The observed lines were fitted to retrieve a 3.5 ns lifetime of the upper state, showing that even with a triple or double excitation quanta in the water subunit, the Ar-D2O and Ar-HDO complexes are long-lived species. © 2013 American Institute of Physics.
BibTeX:
@article{DidricheFoeldes2013,
  author = {Didriche, K. and Földes, T.},
  title = {High resolution spectroscopy of the Ar-D2O and Ar-HDO molecular complexes in the near-infrared range},
  journal = {Journal of Chemical Physics},
  year = {2013},
  volume = {138},
  article number = {104307},
  doi = {10.1063/1.4794161}
}
Abstract: A high-resolution spectrum of the acetylene-water complex has been recorded in the overtone range. Two bands of C2H2-D2O were analysed, corresponding to the overtone excitations of either the acetylene or the water units. The vibrational shifts and the upper states rotational constants were retrieved, demonstrating that the geometry of the complex is only slightly modified by the excitation. A larger linewidth was observed for the 2CH band than for the 2OD + DOD band, probably due to the direct coupling of the 2CH excitation with the dissociation coordinate. © 2013 Copyright Taylor and Francis Group, LLC.
BibTeX:
@article{DidricheFoeldes2013a,
  author = {Didriche, K. and Földes, T.},
  title = {High-resolution overtone spectra of molecular complexes},
  journal = {Molecular Physics},
  year = {2013},
  volume = {111},
  pages = {355-364},
  doi = {10.1080/00268976.2012.752880}
}
Abstract: Spectroscopic results are presented concerning the 2CH excitation around 1.5 mm in van der Waals complexes of acetylene (C2H2) with Ar, Kr, N2, CO2, N2O and C2H 2. Many are reviewed from the literature, with some updates. Previously unpublished results are also presented, concerning the mechanism of formation of C2H2-Ar in the supersonic jet, the assignment of new spectral structures in C2H2-N2O, and the first observation of 2CH excitation in C2H2-Ne, C 2H2-H2O, C2H2-D 2O and (C2H2)n. Lifetimes of these 2CH vibrationally excited dimers are discussed. © 2012 Taylor and Francis.
BibTeX:
@article{DidricheFoeldesLauzinEtAl2012,
  author = {Didriche, K. and Földes, T. and Lauzin, C. and Golebiowski, D. and Liévin, J. and Herman, M.},
  title = {Experimental 2CH excitation in acetylene-containing van der Waals complexes},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2781-2796},
  doi = {10.1080/00268976.2012.705347}
}
Abstract: A preliminary analysis of the 2CH excitation band in C2H 2-N2O in the 1.5 mm range (K. Didriche, C. Lauzin, P. Macko, M. Herman and W.J. Lafferty, Chem. Phys. Letters 469, 35 (2009).), only considering 117 low J-, and Ka-vibration-rotation lines, is significantly extended thanks to the analysis of new spectra including very regular series of lines with J/Ka up to 31/15. 1271 b-type lines were assigned. Perturbations are briefly discussed. The rotational temperature in the experiments is estimated to be 20K and the upper state mean half-time is 1.6 ns for non perturbed levels. The previous analyses of the 2CH + torsion band in C2H2-N2O and in C2H 2-CO2 (C. Lauzin, K. Didriche, T. Földes and M. Herman, Mol. Phys. 109, 2105 (2011).), are also extended to include 286 and 234 lines, respectively, also correcting for calibration errors. New rotational constants are obtained using a rigid rotor Hamiltonian by simultaneously fitting the ground, 2CH and 2CH + torsion states in C2H2-N 2O, and the latter state, only, in C2H2-CO 2. © 2012 Taylor and Francis.
BibTeX:
@article{DidricheFoeldesLauzinEtAl2012a,
  author = {Didriche, K. and Földes, T. and Lauzin, C. and Herman, M.},
  title = {The 2CH excitation band in C2H2-N2O and 2CH+torsion combination bands in C2H2-N2O and C2H2-CO2},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2773-2779},
  doi = {10.1080/00268976.2012.713523}
}
Abstract: The Π (11) ← Σ (00) 2NH (ν1+ν3) band of the NH3-Ar van der Waals complex formed in a supersonic jet expansion, with origin at 6628 cm -1 was recorded at high-resolution using cavity ring down spectroscopy. The analysis leads to upper state rotational constants and J-dependent predissociation lifetimes estimated from linewidth analysis, with a mean value about 0.6 ns. © 2013 AIP Publishing LLC.
BibTeX:
@article{DidricheFoeldesVanfleterenEtAl2013,
  author = {Didriche, K. and Földes, T. and Vanfleteren, T. and Herman, M.},
  title = {Communication: Overtone (2NH) spectroscopy of NH3-Ar},
  journal = {Journal of Chemical Physics},
  year = {2013},
  volume = {138},
  article number = {181101},
  doi = {10.1063/1.4804421}
}
Abstract: The prototype role of this simple four-atom molecule is highlighted in high-resolution vibration-rotation spectroscopy, intramolecular dynamics, and astrochemistry. © 2010 Elsevier B.V. All rights reserved.
BibTeX:
@article{DidricheHerman2010,
  author = {Didriche, K. and Herman, M.},
  title = {A four-atom molecule at the forefront of spectroscopy, intramolecular dynamics and astrochemistry: Acetylene},
  journal = {Chemical Physics Letters},
  year = {2010},
  volume = {496},
  pages = {1-7},
  doi = {10.1016/j.cplett.2010.07.031}
}
Abstract: CW-cavity ring down spectroscopy was used to record the spectrum of 12C 2H 2-N 2 in a free jet expansion around the 2CH acetylene band. Twenty lines were assigned thanks to combination differences, which were combined with literature values leading to the retrieval of ground state rotational constants consistent for a broader set of J″. Effective rotational constants, the band origin and the estimation of the lifetime of the perturbed upper state are determined. © 2012 Elsevier B.V. All rights reserved.
BibTeX:
@article{DidricheLauzinFoeldes2012,
  author = {Didriche, K. and Lauzin, C. and Földes, T.},
  title = {Observation of the linear C 2H 2-N 2 van der Waals complex in the 2CH range using CW-CRDS},
  journal = {Chemical Physics Letters},
  year = {2012},
  volume = {530},
  pages = {31-34},
  doi = {10.1016/j.cplett.2012.01.072}
}
Abstract: The experimental set-up FANTASIO, for 'Fourier trANsform, Tunable diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn' (M. Herman, K. Didriche, D. Hurtmans, B. Kizil, P. Macko, A. Rizopoulos and P. Van Poucke, Mol. Phys. 105, 815 (2007)) built in Brussels has been updated. The turbomolecular pumping system of the supersonic expansion has been doubled and new mirrors, with reflectivity 99.999% instead of 99.99%, have been set in the CW-cavity ring down spectrometer probing jet-cooled molecules. The changes all together result in a signal to noise increased by up to a factor 10, around 1.5 μm. These improvements are demonstrated with various acetylene data in the 2CH excitation range, including the assignment of a new sub-band of acetylene-Ar, with K'-K'' = 2-3. The focus is set on the acetylene dimer. Overtone sub-bands, with b- and a-type structures, are identified for the first time in the literature. They are assigned to vibrational excitation in the hat and body units of the T shaped dimer, respectively. The relevance of the overtone data on acetylene dimers for space remote sensing is highlighted. © 2010 Taylor & Francis.
BibTeX:
@article{DidricheLauzinFoldesEtAl2010,
  author = {Didriche, K. and Lauzin, C. and Foldes, T. and De Ghellinck, X.D.V. and Herman, M.},
  title = {The FANTASIO+ set-up to investigate jet-cooled molecules: Focus on overtone bands of the acetylene dimer},
  journal = {Molecular Physics},
  year = {2010},
  volume = {108},
  pages = {2155-2163},
  doi = {10.1080/00268976.2010.489525}
}
Abstract: CW-cavity ring down spectroscopy was used to record in a free jet expansion the spectrum of the absorption band in (12C2H 2)2 with origin at 6547.6 cm-1. It is a perpendicular band and corresponds to 2CH excitation in the hat unit of the T-shaped dimer. Calibration (better than ±1 × 10-3 cm-1 accuracy) and ring-down time (130 μs) were improved compared to a previous contribution (Didriche et al. Mol. Phys., 2010, 108, 2158-2164). A line-by-line analysis was achieved. Three series of lines were identified involving levels with A1 +, E+ and B 1 + ground state tunneling symmetries, confirming the spectral and symmetry analyses reported in the literature for the 1CH excitation band (Fraser et al. J. Chem. Phys., 1988, 89, 6028-6045). 164 vibration-rotation-tunneling lines were assigned in the K′a- K″a= 2-3,0-1,2-1 and 4-3 sub-bands and effective rigid rotor vibration-rotation constants were obtained by simultaneously fitting 1CH and 2CH lines with the same symmetry series. Perturbations affecting the Ka stacks, in particular, are reported. The tunneling frequency in 2CH is estimated to be ν2CH tunn = 270 MHz for the Ka = 0 stack. The rotational temperature is determined to be 23 K from relative line intensities and the lifetime of the dimer in the 2CH hat state is estimated to be 1 ns from individual line widths. © the Owner Societies 2011.
BibTeX:
@article{DidricheLauzinFoeldesEtAl2011,
  author = {Didriche, K. and Lauzin, C. and Földes, T. and Golebiowski, D. and Herman, M. and Leforestier, C.},
  title = {High resolution overtone spectroscopy of the acetylene van der Waals dimer, (12C2H2)2},
  journal = {Physical Chemistry Chemical Physics},
  year = {2011},
  volume = {13},
  pages = {14010-14018},
  doi = {10.1039/c1cp20561g}
}
Abstract: A slit nozzle supersonic expansion containing C2H2 (246 sccm) and N2O (355 sccm) seeded into Ar (1260 sccm) is investigated using CW cavity ring-down spectroscopy, in the 1.5 μm range. The C2H2-N2O van der Waals complex is observed around the 2CH acetylenic band. Despite strong perturbations, 117 b-type lines are assigned. Their combined fit with published microwave data leads to new upper state and improved lower state rotational constants. The Lorentzian width of the assigned line profiles sets the mean lifetime to 1.6 ns. The rotational temperature is estimated to be 15 K from the comparison between observed and simulated spectra. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{DidricheLauzinMackoEtAl2009,
  author = {Didriche, K. and Lauzin, C. and Macko, P. and Herman, M. and Lafferty, W.J.},
  title = {Observation of the C2H2-N2O van der Waals complex in the overtone range using CW-CRDS},
  journal = {Chemical Physics Letters},
  year = {2009},
  volume = {469},
  pages = {35-37},
  doi = {10.1016/j.cplett.2008.12.037}
}
Abstract: A supersonic expansion containing acetylene seeded into Ar and produced from a circular nozzle is investigated using CW/cavity ring down spectroscopy, in the 1.5 μm range. The results, also involving experiments with pure acetylene and acetylene-He expansions, as well as slit nozzles, demonstrate that the denser central section in the expansion is slightly heated by the formation of acetylene aggregates, resulting into a dip in the monomer absorption line profiles. Acetylene-Ar aggregates are also formed at the edge of the circular nozzle expansion cone. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{DidricheLauzinMackoEtAl2008,
  author = {Didriche, K. and Lauzin, C. and Macko, P. and Lafferty, W.J. and Saykally, R.J. and Herman, M.},
  title = {On the role of molecular clustering on infrared absorption line shapes of acetylene in a supersonic expansion},
  journal = {Chemical Physics Letters},
  year = {2008},
  volume = {463},
  pages = {345-348},
  doi = {10.1016/j.cplett.2008.08.086}
}
Abstract: The hydrodynamic structure of an axisymmetric supersonic expansion can be regarded as a series of concentric divergent cones, with decreasing particle densities as the cone angle increases. Different groups of molecules therefore contribute to high-resolution absorption line shapes when optically probing the expansion in a direction perpendicular to the jet axis. These groups are distinguished by the cone angle, inducing a specific Doppler shift, and by the particle density, contributing a specific weight to the absorption intensity. As a result different broader line profiles are observed compared to room temperature spectra. This effect is investigated here selecting as the working example the R(0), ν3 absorption line in N2O recorded using a Fourier transform interferometer. Independent impact pressure and quadrupole mass spectrometric measurements are performed leading to two complementary maps of the expansion, allowing the recorded absorption line shape to be quantitatively modeled. © 2006 Elsevier Ltd. All rights reserved.
BibTeX:
@article{DidricheMackoHermanEtAl2007,
  author = {Didriche, K. and Macko, P. and Herman, M. and Thiévin, J. and Benidar, A. and Georges, R.},
  title = {Investigation of the shape of the R(0) absorption line in ν3, N2O recorded from an axisymmetric supersonic free jet expansion},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2007},
  volume = {105},
  pages = {128-138},
  doi = {10.1016/j.jqsrt.2006.10.002}
}
Abstract: A resumé of Boys' approach to configuration interaction calculations is presented, and a program suitable to perform such calculations is described in some detail. The results of a preliminary calculation on water, together with some timings are presented. © 1974 Springer-Verlag.
BibTeX:
@article{DiercksenSutcliffe1974,
  author = {Diercksen, G.H.F. and Sutcliffe, B.T.},
  title = {Configuration interaction by the method of bonded functions, some preliminary calculations},
  journal = {Theoretica Chimica Acta},
  year = {1974},
  volume = {34},
  pages = {105-114},
  doi = {10.1007/BF00551361}
}
Abstract: The absorption spectrum of 12C2H2 has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the spectral region 10 140-10 600 cm−1, where three absorption bands were previously observed by Fourier transform spectroscopy. Thirteen bands starting from the vibrational ground state could be detected and rotationally analyzed. All corresponding excited vibrational levels could be assigned using the polyad model (M. I. El Idrissi, J. Liévin, A. Campargue, and M. Herman, J. Chem. Phys. 110, 2074-2086 (1999)). The assignment procedure is detailed and relative intensity features are discussed. © 2002 Elsevier Science (USA).
BibTeX:
@article{DingHermanCampargue2002,
  author = {Ding, Y. and Herman, M. and Campargue, A.},
  title = {Iclas of 12c2h2 between 10 140 and 10 600 cm−1},
  journal = {Journal of Molecular Spectroscopy},
  year = {2002},
  volume = {212},
  pages = {125-129},
  doi = {10.1006/jmsp.2002.8518}
}
BibTeX:
@article{DoggettSutcliffe1998,
  author = {Doggett, G. and Sutcliffe, B.},
  title = {A modern approach to L-S coupling in the theory of atomic spectra},
  journal = {Journal of Chemical Education},
  year = {1998},
  volume = {75},
  pages = {110-114}
}
Abstract: Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which are controlled by changes in the surface temperature and ozone variation due to specific processes, such as the ozone hole in the polar regions and stratospheric intrusions into the troposphere. © Author(s) 2015.
BibTeX:
@article{DonikiHurtmansClarisseEtAl2015,
  author = {Doniki, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Worden, H.M. and Bowman, K.W. and Coheur, P.-F.},
  title = {Instantaneous longwave radiative impact of ozone: An application on IASI/MetOp observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12971-12987},
  doi = {10.5194/acp-15-12971-2015}
}
Abstract: A direct simulation Monte Carlo (DSMC) method is applied to model collisions between He buffer gas atoms and ammonia molecules within a buffer gas cell. State-to-state cross sections, calculated as a function of the collision energy, enable the inelastic collisions between He and NH3 to be considered explicitly. The inclusion of rotational-state-changing collisions affects the translational temperature of the beam, indicating that elastic and inelastic processes should not be considered in isolation. The properties of the cold molecular beam exiting the cell are examined as a function of the cell parameters and operating conditions; the rotational and translational energy distributions are in accord with experimental measurements. The DSMC calculations show that thermalisation occurs well within the typical 10-20 mm length of many buffer gas cells, suggesting that shorter cells could be employed in many instances - yielding a higher flux of cold molecules. � 2017 Author(s).
BibTeX:
@article{DoppelbauerSchullianLoreauEtAl2017,
  author = {Doppelbauer, M.J. and Schullian, O. and Loreau, J. and Vaeck, N. and Van Der Avoird, A. and Rennick, C.J. and Softley, T.P. and Heazlewood, B.R.},
  title = {Using a direct simulation Monte Carlo approach to model collisions in a buffer gas cell},
  journal = {Journal of Chemical Physics},
  year = {2017},
  volume = {146},
  article number = {044302},
  doi = {10.1063/1.4974253}
}
Abstract: The composition of the vapour in equilibrium with lead oxide (yellow rhombic form β) in the temperature interval 1000-1150°K was determined mass spectrometrically. The predominant species are PbO, Pb2O 2, Pb3O3 and Pb4O4. From the partial PbO pressures measured here as well as those based on a re-interpretation of the literature data, taking the presence of the polymers into account, the dissociation energy of the molecule PbO was calculated: D 0°(PbO) = 88.4±l-4 kcal/mole. The enthalpy ΔH 298° of the reactions: Pb2O2(g) →2 PbO(g), Pb3O3(g) →3 PbO(g), Pb4O 4(g) →4 PbO(g), is 63.4±4, 126.4±6.0 and 202.0±10.0 kcal/mole respectively.
BibTeX:
@article{DrowartColinExsteen1965,
  author = {Drowart, J. and Colin, R. and Exsteen, G.},
  title = {Mass-spectrometric study of the vaporization of lead monoxide: Dissociation energy of PbO},
  journal = {Transactions of the Faraday Society},
  year = {1965},
  volume = {61},
  pages = {1376-1383},
  doi = {10.1039/tf9656101376}
}
Abstract: The mass spectrometric study of the vaporization of the compounds GeO 2(hex) and GeO(am) and of the mixture GeO2(hex)+Ge(c) made it possible to establish their mode of vaporization: GeO2(hex) →GeO(g)+1/2O2 (I) n GeO(am)→(GwO)n(g) (n = 1,2,3), (II) (n/2)GeO2(hex) + (n/2)Ge(c)→(GeO)n(g) (n = 1,2,3). (III) The enthalpies of vaporization are ΔH298° (I) = 124.3±2.4 kcal/mole; ΔH298°(II, n = 1) = 53.1± 1.0 kcal/mole; ΔH298°(III, n = 1) = 57.5±1.0 kcal/mole. The polymerization energies are ΔH 298° (GeO-GeO) = 44.7±3.0 kcal/mole; ΔH 298°(GeO-GeO-GeO) = 88.5±5.0 kcal/mole. Total pressures given in the literature were re-interpreted taking the presence of the polymers into account. The heat of formation of the metastable compound GeO(am) is ΔHf°(GeO) = -60.8±1.4 kcal/mole. The dissociation energy of the gaseous molecule GeO is D0°(GeO) = 156.2±1.9 kcal/mole.
BibTeX:
@article{DrowartDegreveVerhaegenEtAl1965,
  author = {Drowart, J. and Degreve, F. and Verhaegen, G. and Colin, R.},
  title = {Thermochemical study of the germanium oxides using a mass spectrometer: Dissociation energy of the molecule GeO},
  journal = {Transactions of the Faraday Society},
  year = {1965},
  volume = {61},
  pages = {1072-1085},
  doi = {10.1039/TF9656101072}
}
Abstract: The dissociation energy of the molecules MgO, CaO, SrO was determined: D0°(MgO) = 86±5; D0°(CaO) = 93±5; D0(SrO) = 102±5 kcal/mole. The ground state was considered to be 1Σ. This choice is discussed. A discussion of the literature values for D0°(MgO, CaO, SrO) is made. The molecule Sr 2O was identified and its atomization energy determined: ΔH0°, at(Sr2O) = 194±6 kcal/mole.
BibTeX:
@article{DrowartExsteenVerhaegen1964,
  author = {Drowart, J. and Exsteen, G. and Verhaegen, G.},
  title = {Mass spectrometric determination of the dissociation energy of the molecules MgO, CaO, SrO and Sr2O},
  journal = {Transactions of the Faraday Society},
  year = {1964},
  volume = {60},
  pages = {1920-1933},
  doi = {10.1039/tf9646001920}
}
Abstract: In order to recognize the importance of ozone (O3) in the troposphere and lower stratosphere in the tropics, a DIAL (differential absorption lidar) tropospheric O3 lidar system (LIO3TUR) was developed and installed at the Université de la Réunion campus site (close to the sea) on Reunion Island (southern tropics) in 1998. From 1998 to 2010, it acquired 427 O3 profiles from the low to the upper troposphere and has been central to several studies. In 2012, the system was moved up to the new Maïdo Observatory facility (2160-l. - metres above mean sea level) where it started operation in February 2013. The current system (LIO3T) configuration generates a 266 beam obtained with the fourth harmonic of a Nd:YAG laser sent into a Raman cell filled up with deuterium (using helium as buffer gas), generating the 289 and 316 beams to enable the use of the DIAL method for O3 profile measurements. The optimal range for the actual system is 6-19ga.m.s.l., depending on the instrumental and atmospheric conditions. For a 1gh integration time, vertical resolution varies from 0.7gkm at 6ga.m.s.l. to 1.3gkm at 19ga.m.s.l., and mean uncertainty within the 6-19gkm range is between 6 and 13g%. Comparisons with eight electrochemical concentration cell (ECC) sondes simultaneously launched from the Maïdo Observatory show good agreement between data sets with a 6.8g% mean absolute relative difference (D) between 6 and 17ga.m.s.l. (LIO3T lower than ECC). Comparisons with 37 ECC sondes launched from the nearby Gillot site during the daytime in a ±24gh window around lidar shooting result in a 9.4g% D between 6 and 19ga.m.s.l. (LIO3T lower than ECC). Comparisons with 11 ground-based Network for Detection of Atmospheric Composition Change (NDACC) Fourier transform infrared (FTIR) spectrometer measurements acquired during the daytime in a ±24gh window around lidar shooting show good agreement between data sets with a D of 11.8g% for the 8.5-16gkm partial column (LIO3T higher than FTIR), and comparisons with 39 simultaneous Infrared Atmospheric Sounding Interferometer (IASI) observations over Reunion Island show good agreement between data sets with a D of 11.3g% for the 6-16gkm partial column (LIO3T higher than IASI). ECC, LIO3TUR and LIO3T O3 monthly climatologies all exhibit the same range of values and patterns. In particular, the Southern Hemisphere biomass burning seasonal enhancement and the ozonopause altitude decrease in late austral winter-spring, as well as the sign of deep convection bringing boundary layer O3-poor air masses up to the middle-upper troposphere in late austral summer, are clearly visible in all data sets. © Author(s) 2017.
BibTeX:
@article{DuflotBarayPayenEtAl2017,
  author = {Duflot, V. and Baray, J.-L. and Payen, G. and Marquestaut, N. and Posny, F. and Metzger, J.-M. and Langerock, B. and Vigouroux, C. and Hadji-Lazaro, J. and Portafaix, T. and De Mazière, M. and Coheur, P.-F. and Clerbaux, C. and Cammas, J.-P.},
  title = {Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): System description, instrumental performance and result comparison with ozone external data set},
  journal = {Atmospheric Measurement Techniques},
  year = {2017},
  volume = {10},
  pages = {3359-3373},
  doi = {10.5194/amt-10-3359-2017}
}
Abstract: Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm-1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO 2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009-2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values. © Author(s) 2013.
BibTeX:
@article{DuflotHurtmansClarisseEtAl2013,
  author = {Duflot, V. and Hurtmans, D. and Clarisse, L. and R'honi, Y. and Vigouroux, C. and De Mazière, M. and Mahieu, E. and Servais, C. and Clerbaux, C. and Coheur, P.-F.},
  title = {Measurements of hydrogen cyanide (HCN) and acetylene (C2H 2) from the Infrared Atmospheric Sounding Interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {917-925},
  doi = {10.5194/amt-6-917-2013}
}
Abstract: We present global distributions of C2H2 and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008-2010. These distributions are obtained with a fast method allowing to retrieve C2H2 abundance globally with a 5 % precision and HCN abundance in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show that there is an overall agreement between the ground-based and space measurements with correlation coefficients for daily mean measurements ranging from 0.28 to 0.81, depending on the site. Global C2H2 and subtropical HCN abundances retrieved from IASI spectra show the expected seasonality linked to variations in the anthropogenic emissions and seasonal biomass burning activity, as well as exceptional events, and are in good agreement with previous spaceborne studies. Total columns simulated by the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are compared to the ground-based FTIR measurements at the four selected stations. The model is able to capture the seasonality in the two species in most of the cases, with correlation coefficients for daily mean measurements ranging from 0.50 to 0.86, depending on the site. IASI measurements are also compared to the distributions from MOZART-4. Seasonal cycles observed from satellite data are reasonably well reproduced by the model with correlation coefficients ranging from g'0.31 to 0.93 for C2H2 daily means, and from 0.09 to 0.86 for HCN daily means, depending on the considered region. However, the anthropogenic (biomass burning) emissions used in the model seem to be overestimated (underestimated), and a negative global mean bias of 1 % (16 %) of the model relative to the satellite observations was found for C2H2 (HCN). © Author(s) 2015.
BibTeX:
@article{DuflotWespesClarisseEtAl2015,
  author = {Duflot, V. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Ngadi, Y. and Jones, N. and Paton-Walsh, C. and Hadji-Lazaro, J. and Vigouroux, C. and De Mazière, M. and Metzger, J.-M. and Mahieu, E. and Servais, C. and Hase, F. and Schneider, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: Global distributions, validation, and comparison with model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {10509-10527},
  doi = {10.5194/acp-15-10509-2015}
}
Abstract: Three scientific ozone products from the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A, retrieved in three different research teams (LA, LATMOS/ULB, LISA) with different retrieval schemes, are characterized and validated using ozonesondes measurements. The characteristics of the products are analyzed in terms of retrieval sensitivity, systematic and random errors, and ability to retrieve the natural variability of ozone and focus on different partial columns from the lower troposphere up to 30 km. The validation covers the midlatitudes and the tropics and the period from January to December 2008. The products present degrees of freedom (DOF) in the troposphere between 1 and 1.2 on average in the midlatitudes and between 1 and 1.4 in the tropics. The DOF are distributed differently on the vertical depending on the profiles and the season: summer leading to a better sensitivity to the lower troposphere, as expected. The error estimates range between 10 and 20% from the lower tropospheric partial columns (0-6 km and 0-8 km for the midlatitudes and the tropics respectively) to the UTLS partial columns (8-16 km and 11-20 km for the midlatitudes and the tropics respectively) for all the products and are about 5% in the stratosphere (16-30 km) and for the column up to 30 km. The main feature that arises from the comparison with the ozonesondes is a systematic overestimation of ozone in the UTLS (between 10 and 25%) by the three products in the midlatitudes and the tropics, attributed to the moderate vertical resolution of IASI and possibly to spectroscopic inconsistencies. The ability of the products to reproduce natural variability of tropospheric ozone is fairly good and depends on the considered season and region. © 2012 Author(s).
BibTeX:
@article{DufourEremenkoGriesfellerEtAl2012,
  author = {Dufour, G. and Eremenko, M. and Griesfeller, A. and Barret, B. and Leflochmoën, E. and Clerbaux, C. and Hadji-Lazaro, J. and Coheur, P.-F. and Hurtmans, D.},
  title = {Validation of three different scientific ozone products retrieved from IASI spectra using ozonesondes},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {611-630},
  doi = {10.5194/amt-5-611-2012}
}
Abstract: We present a line profile study for two lines in the 2v3 band of CH4 recorded with a frequency stabilized tunable diode laser spectrometer. The broadening and narrowing (Dicke effect) parameters of the R(0) line perturbed by N2, O2, and He are derived from a simultaneous fitting of spectra at pressures from 20 to 300 Torr by using the soft and hard collision models. These parameters are determined for the A and F components of the unresolved R(3) manifold perturbed by N2, Ar, and He from the line profile analysis of spectra at pressures between 50 and 500 Torr. The line mixing effect between the two F components is also taken into account and the absorber speed dependent effect on broadening is estimated for N2 and Ar.
BibTeX:
@article{DufourHurtmansHenryEtAl2003,
  author = {Dufour, G. and Hurtmans, D. and Henry, A. and Valentin, A. and Lepère, M.},
  title = {Line profile study from diode laser spectroscopy in the 12CH4 2v3 band perturbed by N2, O2, Ar, and He},
  journal = {Journal of Molecular Spectroscopy},
  year = {2003},
  volume = {221},
  pages = {80-92},
  doi = {10.1016/S0022-2852(03)00178-4}
}
Abstract: Simultaneous ultraviolet (UV) and infrared (IR) measurements of ozone concentration in air in the 1200-300 ppbv range have been performed using the ultraviolet absorption in the Hartley band at 0.2537 μm and the infrared absorption of a doublet at 9.507 μm in the ν3 vibration-rotation band. Infrared concentration measurements were achieved using the tunable diode laser spectrometer of LPMA in Paris with interferometric control of the emitted wavelength while the UV concentration measurements were performed with the 49PS Megatec ozone generator of the Bureau National de Métrologie (BNM). The simultaneous recording of spectra of a reference cell filled with pure distilled ozone and of a low concentration mixture inside a long absorbing path Herriott cell allows to carry out infrared concentration measurements with an accuracy of the same order as the ultraviolet ones and provides the instrumental parameters of the spectrometer corresponding to each concentration measurement, which reduces systematic errors. Within the respective absolute uncertainties proper to the two techniques, no systematic discrepancy was evidenced between the IR and the UV measurements. The ozone ultraviolet absorption coefficient value determined by Hearn (308.3±4 cm-1 atm-1) and used by the BNM and the National Institute of Standards and Technology (NIST) is confirmed by the present work. © 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{DufourValentinHenryEtAl2004,
  author = {Dufour, G. and Valentin, A. and Henry, A. and Hurtmans, D. and Camy-Peyret, C.},
  title = {Concentration measurements of ozone in the 1200-300 ppbv range: An intercomparison between the BNM ultraviolet standard and infrared methods},
  journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy},
  year = {2004},
  volume = {60},
  pages = {3345-3352},
  doi = {10.1016/j.saa.2003.12.056}
}
Abstract: Extensive self-consistent multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and subsequent relativistic configuration interaction calculations are performed for 262 states belonging to the 15 configurations 2s 22p2, 2s2p3, 2p4, 2s 22p3l, 2s2p23l, 2p33l and 2s22p4l(l = 0,1,2) in selected carbon-like ions from Ar XIII to Zn XXV. Electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with existing theoretical calculations and data from the Chianti and NIST databases. In addition, Landé gJ-factors and radiative electric dipole transition rates are given for all ions. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. © 2014 ESO.
BibTeX:
@article{EkmanJoenssonGustafssonEtAl2014,
  author = {Ekman, J. and Jönsson, P. and Gustafsson, S. and Hartman, H. and Gaigalas, G. and Godefroid, M.R. and Froese Fischer, C.},
  title = {Calculations with spectroscopic accuracy: Energies, transition rates,and Lande gJ-factors in the carbon isoelectronic sequence from Ar XIII to Zn XXV},
  journal = {Astronomy and Astrophysics},
  year = {2014},
  volume = {564},
  article number = {A24},
  doi = {10.1051/0004-6361/201323163}
}
Abstract: We measured 305 absolute line intensities in the ν1 + ν3(∑u+)-0(∑8 +) band of 12C2H2 and 13C12CH2 and the ν1 + ν2 + (ν41 + ν5-1)0(∑u+)- 0(∑8+), ν1 + ν3 + ν41 (Πg)-ν41 (Πg), and ν1 + ν3 + ν51 (Πu)-ν51(Πu) bands of the main isotopomer, all observed near 1.5 μm. The absolute intensity of these bands are respectively 6.4882 (34), 0.12337 (10), 0.083746 (71), 0.58771 (28), and 0.32126 (11) cm-2 atm-1 at 296 K. In addition, we also determined Herman-Wallis factors for the first time in this spectral region. © 2002 Elsevier Science (USA).
BibTeX:
@article{ElHachtoukiVanderAuwera2002,
  author = {El Hachtouki, R. and Vander Auwera, J.},
  title = {Absolute line intensities in acetylene: The 1.5-μm region},
  journal = {Journal of Molecular Spectroscopy},
  year = {2002},
  volume = {216},
  pages = {355-362},
  doi = {10.1006/jmsp.2002.8660}
}
Abstract: All 253 vibrational levels in the ground electronic state of 12C2H2 with assigned rotational structure reported in the literature from absorption, stimulated emission pumping, and dispersed laser induced fluorescence spectroscopic investigations are gathered. They cover the range up to 18915 cm-1. Some 219 of these energies are simultaneously fitted using the same so-called Cluster model based on the emergence of three constants of the motion, as previously used to deal with the vibrational energy levels up to 12 000 cm-1 [Abbouti Temsamani and Herman, J. Chem. Phys. 103, 5931 (1995)]. Thirty-nine vibrational constants are produced. The rms value of the fit is 0.81 cm-1. Principal rotational constants are predicted for all levels, which satisfactorily compare with the experimental results. Problems are demonstrated to concern a fraction of the 34 remaining levels only. Thus, the adequacy of the model is fully confirmed. The remaining problems are discussed and globally attributed to problems of a vibration-rotation nature. A comprehensive listing of calculated vibrational energies for all k sublevels up to 15 000 cm-1, including predicted Bv, values and assignments is made available. © 1999 American Institute of Physics.
BibTeX:
@article{ElIdrissiLievinCampargueEtAl1999,
  author = {El Idrissi, M.I. and Liévin, J. and Campargue, A. and Herman, M.},
  title = {The vibrational energy pattern in acetylene (IV): Updated global vibration constants for 12C2H2},
  journal = {Journal of Chemical Physics},
  year = {1999},
  volume = {110},
  pages = {2074-2086},
  doi = {10.1063/1.477817}
}
Abstract: The results of ab initio calculations at the MP2 level of theory are presented, which provide refined equilibrium geometrical parameters and better characterization of the vibrational normal modes in propyne (CH3C2H). These results help performing the vibrational analysis of the high resolution Fourier transform absorption spectrum of this molecule which has been recorded between 2000 and 10 200 cm-1. The vibrational assignment criteria also include, in particular, the detailed identification of the band shape based on the observed rotational structure that is resolved for most bands. Some 46 bands are observed and their band shape identified in most cases. Among the bands newly reported, some 14 are vibrationally assigned, three of them tentatively. The relative intensity of all observed bands is estimated from the spectra. Approximate ζ rotational constants are obtained for ν3 + ν6 (0.074) and 2ν1 +ν8 (0.38). The results are merged with those of the previous literature, leading to list the origin of 118 vibrational bands, from which an extensive set of vibrational constants is extracted. Two polyad quantum numbers emerge from the vibrational energy pattern: Nsb = 3v1 + v3 + 2v5 + v9 and Ns = v1 + v3, supported by the ν1 with ν3+ ν5 and ν1 with ν3+ 2ν9 anharmonic resonances. © 2001 Elsevier Science B.V.
BibTeX:
@article{ElIdrissiLievinHermanEtAl2001,
  author = {El Idrissi, M.I. and Liévin, J. and Herman, M. and Campargue, A. and Graner, G.},
  title = {The vibrational energy pattern in propyne (12CH3 12C2H)},
  journal = {Chemical Physics},
  year = {2001},
  volume = {265},
  pages = {273-289},
  doi = {10.1016/S0301-0104(01)00308-1}
}
Abstract: We report on the first detailed rovibrational analysis in 1,2-dichloroethane. It concerns the a-type v16 absorption band of gaseous trans-1,2-dichloroethane at 1232 cm-1, which we have recorded using a Fourier transform interferometer, under room temperature and jet-cooled experimental conditions. The rotational analysis of the almost diatomic-like prominent R and P structures in v16 is performed for trans-1,2-12C2H4 35Cl2 and trans-1,2-12C2H4 35Cl37Cl. The nuclear spin statistics is discussed for various isotopomers and isomers of 1,2-dichloroethane. The complex absorption pattern observed at the band center is tentatively assigned in terms of overlapping Q branches, arising from fundamental bands involving different isotopomers in natural abundance (with 35Cl and 37Cl), and from related hot bands involving the three lowest vibrational modes in the molecule, v6, v10, and v18. © 1997 Academic Press.
BibTeX:
@article{ElYoussoufiGeorgesLievinEtAl1997,
  author = {El Youssoufi, Y. and Georges, R. and Liévin, J. and Herman, M.},
  title = {High-Resolution Spectroscopic Investigation of v16 in trans-1,2-Dichloroethane},
  journal = {Journal of Molecular Spectroscopy},
  year = {1997},
  volume = {186},
  pages = {239-245}
}
Abstract: Extensive ab initio calculations are performed concerning N2O4 in the ground electronic state, at the MP4 and CMRCI levels of theory, using the 6-31G* and cc-pVTZ basis sets. Special care is devoted to internal degrees of freedom characterizing the quasi van der Waals NN bond, namely the torsion and the NN stretch vibrational modes. The role of the methodology is investigated with the help of previous literature results. It is shown that most properties are significantly better described by MP4 than by MP2, but that a variational multireference method, like CMRCI, is however required for all properties linked to the NN bond. The ab initio vibrational analysis is merged with the one of absorption spectra recorded at medium resolution between 700 and 7000 cm-1, using a Fourier transform interferometer. The resulting set of effective vibrational frequencies and anharmonicities is provided. The height of the torsional potential energy barrier is calculated to be 2000 cm-1, at the best level of theory (CMRCI/cc-pVTZ), in agreement with the highest experimental value available. © 1997 Elsevier Science B.V.
BibTeX:
@article{ElyoussoufiHermanLievinEtAl1997,
  author = {Elyoussoufi, Y. and Herman, M. and Liévin, J. and Kleiner, I.},
  title = {Ab initio and experimental investigation of the vibrational energy pattern in N2O4: The mid and near infrared ranges},
  journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy},
  year = {1997},
  volume = {53},
  pages = {881-894},
  doi = {10.1016/S1386-1425(96)01774-X}
}
Abstract: An overview of the achievements and the current state of knowledge on reactive nitrogen in Europe, focusing on deposition, critical load exceedances, and modeled and measured trends.
BibTeX:
@article{ErismanDammersVanDammeEtAl2015,
  author = {Erisman, J.W. and Dammers, E. and Van Damme, M. and Soudzilovskaia, N. and Schaap, M.},
  title = {Trends in EU nitrogen deposition and impacts on ecosystems},
  journal = {EM: Air and Waste Management Association's Magazine for Environmental Managers},
  year = {2015},
  volume = {65},
  pages = {31-35}
}
Abstract: About 400 absolute intensities have been measured for six bands(5 Σ-Σ and 1 Π-Σ bands) of 16O12C32S in the region of the ν1 + ν3 band near 3.4 μm. The majority of these bands exhibit weak to very strong Herman-Wallis behavior as a result of various anharmonic and l-type resonances between the upper levels involved. The individual line intensities were treated in two different ways. First, they were fitted to usual effective formulae, leading to the band strengths and Herman-Wallis factors. Second, the line intensities in the five Σ-Σ bands were fitted to a model taking explicitly into account the various anharmonic and I-type resonances between the upper levels. This treatment showed that these resonances quantitatively explain to a large extent the Herman-Wallis behavior observed. © 1995 Academic Press, Inc.
BibTeX:
@article{ErreraVanderauweraBelafhalEtAl1995,
  author = {Errera, Q. and Vanderauwera, J. and Belafhal, A. and Fayt, A.},
  title = {Absolute intensities in 16o12c32s: The 2500-3100 cm-1},
  journal = {Journal of Molecular Spectroscopy},
  year = {1995},
  volume = {173},
  pages = {347-369},
  doi = {10.1006/jmsp.1995.1240}
}
Abstract: New measurements of the absorption cross sections of gaseous benzene, toluene, meta-, ortho-, and para-xylene have been performed with a Fourier transform spectrometer Bruker IFS120 M at the resolution of 1 cm-1 over the 30 000-42 000 cm-1 spectral range. The recordings were carried out under different pressure and temperature conditions with pure samples. The effect of the temperature on the absorption cross sections is investigated. Comparison with the literature shows large differences, largely attributed to the experimental difficulties encountered during these previous measurements and to a resolution effect. To our knowledge, it is the first time that such a dataset of UV absorption cross sections with temperature dependence is reported in the literature. Such data should be useful for upcoming remote sensing applications, such as atmospheric studies both on Earth and on other planets. © 2008 Elsevier Ltd. All rights reserved.
BibTeX:
@article{FallyCarleerVandaele2009,
  author = {Fally, S. and Carleer, M. and Vandaele, A.C.},
  title = {UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2009},
  volume = {110},
  pages = {766-782},
  doi = {10.1016/j.jqsrt.2008.11.014}
}
Abstract: Considering the unique role that water in its vapor phase plays in atmospheric physical and chemical processes, there is a need for accurate spectroscopic parameters for this molecule. Long-pathlength Fourier transform spectra of water vapor with synthetic air as the perturbing gas were recorded and analyzed in the 26,000-13,000 cm-1 spectral region. New measurements of air-broadening and air-shifting parameters, with associated uncertainties are presented for about 5000 lines. These data complement our existing database, providing a homogeneous and extensive dataset extending from 26,000 to 9250 cm-1. Comparisons with the two most frequently used HITRAN and ESA databases as well as with other literature data available are made. Agreements and discrepancies are underlined and briefly discussed. © 2003 Elsevier Ltd. All rights reserved.
BibTeX:
@article{FallyCoheurCarleerEtAl2003,
  author = {Fally, S. and Coheur, P.-F. and Carleer, M. and Clerbaux, C. and Colin, R. and Jenouvrier, A. and Mérienne, M.-F. and Hermans, C. and Vandaele, A.C.},
  title = {Water vapor line broadening and shifting by air in the 26,000-13,000 cm-1 region},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2003},
  volume = {82},
  pages = {119-131},
  doi = {10.1016/S0022-4073(03)00149-3}
}
Abstract: Absorption spectra of molecular oxygen were measured in the laboratory under temperature and pressure conditions prevailing in the Earth's atmosphere. Spectra of pure O2, O2+N2, and O2+Ar were recorded in the 41 700 to 33 000 cm-1 region (240-300 nm) at a maximal optical path difference of 0.45 cm using a Fourier transform spectrometer and a multiple reflection gas cell. The different components of the spectra, namely the discrete bands of the three Herzberg systems, the Herzberg continuum, and the collision-induced diffuse Wulf bands, were separated. The contribution of the Herzberg bands was first subtracted using the line parameters determined previously from high-resolution data. Spectra recorded at various pressures then made it possible to determine by linear regression the intensity of the Wulf bands and the Herzberg continuum. The characteristics of the Wulf bands have been investigated in details: vibrational analysis, pressure effect, foreign gas effect, and a simulated spectrum are reported. The Herzberg continuum cross section is determined below the dissociation limit. A comparison with literature data is given. The new O2 absorption cross sections and O2-O2 collision-induced absorption cross sections are useful in connection with atmospheric measurements of ozone and other trace gases in the UV spectral region.
BibTeX:
@article{FallyVandaeleCarleerEtAl2000,
  author = {Fally, S. and Vandaele, A.C. and Carleer, M. and Hermans, C. and Jenouvrier, A. and Mérienne, M.-F. and Coquart, B. and Colin, R.},
  title = {Fourier transform spectroscopy of the O2 Herzberg bands. III. Absorption cross sections of the collision-induced bands and of the Herzberg continuum},
  journal = {Journal of molecular spectroscopy},
  year = {2000},
  volume = {204},
  pages = {10-20},
  doi = {10.1006/jmsp.2000.8204}
}
Abstract: All known vibration-rotation absorption lines of 13CH 12CH accessing levels up to 6750 cm-1 were gathered from the literature. They were fitted simultaneously to J-dependent Hamiltonian matrices exploiting the well known vibrational polyad or cluster block diagonalization, in terms of the pseudo-quantum-numbers Ns=v 1+v2+v3 and Nr=5v 1+3v2+5v3+v4+v5, and accounting also for I parity and elf symmetry properties. The anharmonic interaction coupling terms known to occur from a pure vibrational fit in this acetylene isotopologue [Robert et al., J. Chem. Phys. 123, 174302 (2005)] were included in the model. A total of 12 703 transitions accessing 158 different (v1v2V3V4v5, l 4l5) vibrational states was fitted with a dimensionless standard deviation of 0.99, leading to the determination of 216 vibration-rotation parameters. The experimental data included very weak vibration-rotation transitions accessing 18 previously unreported states, some of them forming Q branches with very irregular patterns. © 2007 American Institute of Physics.
BibTeX:
@article{FaytRobertDiLonardoEtAl2007,
  author = {Fayt, A. and Robert, S. and Di Lonardo, G. and Fusina, L. and Tamassia, F. and Herman, M.},
  title = {Vibration-rotation energy pattern in acetylene:13CH 12CH up to 6750 cm-1},
  journal = {Journal of Chemical Physics},
  year = {2007},
  volume = {126},
  article number = {114303},
  doi = {10.1063/1.2464101}
}
Abstract: To estimate the sea level rise (SLR) originating from changes in surface mass balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional), forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5) general circulation models (GCMs). Our results indicate that in a warmer climate, mass gain from increased winter snowfall over the GrIS does not compensate mass loss through increased meltwater run-off in summer. Despite the large spread in the projected near-surface warming, all the MAR projections show similar non-linear increase of GrIS surface melt volume because no change is projected in the general atmospheric circulation over Greenland. By coarsely estimating the GrIS SMB changes from GCM output, we show that the uncertainty from the GCM-based forcing represents about half of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a GrIS SMB decrease equivalent to a mean SLR of +4±2cm and +9±4cm for the RCP (Representative Concentration Pathways) 4.5 and RCP 8.5 scenarios respectively. These estimates do not consider the positive melt-elevation feedback, although sensitivity experiments using perturbed ice sheet topographies consistent with the projected SMB changes demonstrate that this is a significant feedback, and highlight the importance of coupling regional climate models to an ice sheet model. Such a coupling will allow the assessment of future response of both surface processes and ice-dynamic changes to rising temperatures, as well as their mutual feedbacks. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX:
@article{FettweisFrancoTedescoEtAl2013,
  author = {Fettweis, X. and Franco, B. and Tedesco, M. and Van Angelen, J.H. and Lenaerts, J.T.M. and Van Den Broeke, M.R. and Gallée, H.},
  title = {Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR},
  journal = {Cryosphere},
  year = {2013},
  volume = {7},
  pages = {469-489},
  doi = {10.5194/tc-7-469-2013}
}
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope shift factors for a set of transitions between low-lying levels of neutral aluminium. These electronic quantities together with observed isotope shifts between different pairs of isotopes provide the changes in mean-square charge radii of the atomic nuclei. Two computational approaches are adopted for the estimation of the mass- and field-shift factors. Within these approaches, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope shift factors. © 2016 American Physical Society.
BibTeX:
@article{FilippinBeerwerthEkmanEtAl2016,
  author = {Filippin, L. and Beerwerth, R. and Ekman, J. and Fritzsche, S. and Godefroid, M. and Jönsson, P.},
  title = {Multiconfiguration calculations of electronic isotope shift factors in Al i},
  journal = {Physical Review A},
  year = {2016},
  volume = {94},
  article number = {062508},
  doi = {10.1103/PhysRevA.94.062508}
}
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope-shift factors for a set of transitions between low-lying states in neutral zinc. These electronic quantities, together with observed isotope shifts between different pairs of isotopes, provide the changes in mean-square charge radii of the atomic nuclei. Within this computational approach, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope-shift factors. © 2017 American Physical Society.
BibTeX:
@article{FilippinBieronGaigalasEtAl2017,
  author = {Filippin, L. and Bieroń, J. and Gaigalas, G. and Godefroid, M. and Jönsson, P.},
  title = {Multiconfiguration calculations of electronic isotope-shift factors in Zn i},
  journal = {Physical Review A},
  year = {2017},
  volume = {96},
  article number = {042502},
  doi = {10.1103/PhysRevA.96.042502}
}
Abstract: Relativistic two-photon decay rates of the 2s1/2 and 2p1/2 states towards the 1s1/2 ground state of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. Highly accurate values are obtained by a simple calculation involving different meshes for the initial, final, and intermediate wave functions and for the calculation of matrix elements. The accuracy of the results with a Coulomb potential is improved by several orders of magnitude in comparison with benchmark values from the literature. The general requirement of gauge invariance is also successfully tested, down to rounding errors. The method provides high accuracies for two-photon decay rates of a particle in other potentials and is applied to a hydrogen atom embedded in a Debye plasma simulated by a Yukawa potential. © 2016 American Physical Society.
BibTeX:
@article{FilippinGodefroidBaye2016,
  author = {Filippin, L. and Godefroid, M. and Baye, D.},
  title = {Relativistic two-photon decay rates with the Lagrange-mesh method},
  journal = {Physical Review A},
  year = {2016},
  volume = {93},
  article number = {012517},
  doi = {10.1103/PhysRevA.93.012517}
}
Abstract: Relativistic dipolar to hexadecapolar polarizabilities of the ground state and some excited states of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. The partial polarizabilities conserving the absolute value of the quantum number κ are also numerically exact with small numbers of mesh points. The ones where |κ| changes are very accurate when using three different meshes for the initial and final wave functions and for the calculation of matrix elements. The polarizabilities of the n=2 excited states of hydrogenic atoms are also studied with a separate treatment of the final states that are degenerate at the nonrelativistic approximation. The method provides high accuracies for polarizabilities of a particle in a Yukawa potential and is applied to a hydrogen atom embedded in a Debye plasma. © 2014 American Physical Society.
BibTeX:
@article{FilippinGodefroidBaye2014,
  author = {Filippin, L. and Godefroid, M. and Baye, D.},
  title = {Relativistic polarizabilities with the Lagrange-mesh method},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2014},
  volume = {90},
  article number = {052520},
  doi = {10.1103/PhysRevA.90.052520}
}
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of isotope shifts for several well-known transitions in neutral magnesium. Relativistic normal and specific mass shift factors as well as the electronic probability density at the origin are calculated. Combining these electronic quantities with available nuclear data, energy and transition level shifts are determined for the Mg26-Mg24 pair of isotopes. Different models for electron correlation are adopted. It is shown that, although valence and core-valence models provide accurate values for the isotope shifts, the inclusion of core-core excitations in the computational strategy significantly improves the accuracy of the transition energies and normal mass shift factors. © 2016 American Physical Society.
BibTeX:
@article{FilippinGodefroidEkmanEtAl2016,
  author = {Filippin, L. and Godefroid, M. and Ekman, J. and Jönsson, P.},
  title = {Core correlation effects in multiconfiguration calculations of isotope shifts in Mg I},
  journal = {Physical Review A},
  year = {2016},
  volume = {93},
  article number = {062512},
  doi = {10.1103/PhysRevA.93.062512}
}
Abstract: Relativistic atomic structure calculations are carried out in alkaline-earth-metal ions using a semiempirical-core-potential approach. The systems are partitioned into frozen-core electrons and an active valence electron. The core orbitals are defined by a Dirac-Hartree-Fock calculation using the grasp2k package. The valence electron is described by a Dirac-like Hamiltonian involving a core-polarization potential to simulate the core-valence electron correlation. The associated equation is solved with the Lagrange-mesh method, which is an approximate variational approach having the form of a mesh calculation because of the use of a Gauss quadrature to calculate matrix elements. Properties involving the low-lying metastable D3/2,5/22 states of Ca+, Sr+, and Ba+ are studied, such as polarizabilities, one- and two-photon decay rates, and lifetimes. Good agreement is found with other theory and observation, which is promising for further applications in alkalilike systems. © 2018 American Physical Society.
BibTeX:
@article{FilippinSchiffmannDohet-EralyEtAl2018,
  author = {Filippin, L. and Schiffmann, S. and Dohet-Eraly, J. and Baye, D. and Godefroid, M.},
  title = {Relativistic semiempirical-core-potential calculations in Ca+, Sr+, and Ba+ ions on Lagrange meshes},
  journal = {Physical Review A},
  year = {2018},
  volume = {97},
  article number = {012506},
  doi = {10.1103/PhysRevA.97.012506}
}
Abstract: We have recorded the dispersed laser-induced fluorescence spectrum of gas-phase C60 ablated from a rotating copper cylinder by 308 nm radiation from a XeCl excimer laser. At vibrational energies below 7000 cm-1 the spectrum consists of three progressions of transitions to the electronic ground state ending on the odd vibrational levels of the lowest frequency t2u mode, with the lowest hu and gu modes as additional origins or on the vibrational levels of the third hg mode with two quanta of the lowest gu mode and the combination hu(1)+gu(1) as the additional origins. At higher vibrational energies, the observed bands become more complex and have yet to be analysed.
BibTeX:
@article{FirthCoheurMitznerEtAl1997,
  author = {Firth, S. and Coheur, P.F. and Mitzner, R. and Carleer, M. and Campbell, E.E.B. and Colin, R. and Kroto, H.W.},
  title = {The dispersed laser-induced fluorescence spectrum of gas-phase C60 at 308 nm},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1997},
  volume = {30},
  pages = {L393-L400},
  doi = {10.1088/0953-4075/30/11/003}
}
Abstract: The multi-configuration Hartree-Fock method, extended to include relativistic effects in the Breit-Pauli approximation (MCHF+BP), has been applied to the study of some forbidden transitions between levels of the 3s 23p3 configuration in the phosphorus sequence. Term energy separations, fine-structure splittings, and E2 and M1 transition rates are reported for S II of interest in astrophysics and for several atomic systems with nuclear charge, Z, in the range 28&lt;or=Z&lt;or=42, where lines have been observed in laboratory plasmas. The results are compared with values derived from observation and with other theories.
BibTeX:
@article{FischerGodefroid1986,
  author = {Fischer, C.F. and Godefroid, M.},
  title = {Multi-configuration Hartree-Fock plus Breit-Pauli results for some forbidden transitions},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1986},
  volume = {19},
  article number = {004},
  pages = {137-148},
  doi = {10.1088/0022-3700/19/2/004}
}
Abstract: Theoretical lifetime trends are reported for all bound singlet states in the n=3 complex of the Mg sequence for Z≤26. Calculations are based on MCHF wavefunctions and include only dipole allowed transitions in the LS scheme. For states that are entering the bound spectrum, the reported lifetime is an upper bound. At sufficiently high Z, all these states can decay only through Δn=0 transitions and several lifetime trends become similar. Implications for the cascade problem in beam-foil spectroscopy are discussed. © 1982.
BibTeX:
@article{FischerGodefroid1982,
  author = {Fischer, C.F. and Godefroid, M.},
  title = {Lifetime trends for the n=3 singlet states in the Mg sequence},
  journal = {Nuclear Instruments and Methods In Physics Research},
  year = {1982},
  volume = {202},
  pages = {307-322},
  doi = {10.1016/0167-5087(82)90411-2}
}
Abstract: Multiconfiguration wave function expansions combined with configuration interaction methods are a method of choice for complex atoms where atomic state functions are expanded in a basis of configuration state functions. Combined with a variational method such as the multiconfiguration Hartree-Fock (MCHF) or multiconfiguration Dirac-Hartree-Fock (MCDHF), the associated set of radial functions can be optimized for the levels of interest. The present review updates the variational MCHF theory to include MCDHF, describes the multireference single and double process for generating expansions and the systematic procedure of a computational scheme for monitoring convergence. It focuses on the calculations of energies and wave functions from which other atomic properties can be predicted such as transition rates, hyperfine structures and isotope shifts, for example. � 2016 IOP Publishing Ltd.
BibTeX:
@article{FischerGodefroidBrageEtAl2016,
  author = {Fischer, C.F. and Godefroid, M. and Brage, T. and J�nsson, P. and Gaigalas, G.},
  title = {Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2016},
  volume = {49},
  article number = {182004},
  doi = {10.1088/0953-4075/49/18/182004}
}
Abstract: Multiconfiguration Breit-Pauli energy levels, lifetimes, and transition data are presented for the lithium sequence in the rangeZ≤ 8. Included are allJ-levels of the six lowest2Lterms, namely those with configuration labels 1s22s, 1s22p, 1s23s, 1s23p, 1s23d, and 1s24s. © 1998 Academic Press.
BibTeX:
@article{FischerSaparovGaigalasEtAl1998,
  author = {Fischer, C.F. and Saparov, M. and Gaigalas, G. and Godefroid, M.},
  title = {Breit-pauli energies, transition probabilities, and lifetimes for 2s, 2p, 3s, 3p, 3d, 4s2llevels of the lithium sequence,Z= 3-8},
  journal = {Atomic Data and Nuclear Data Tables},
  year = {1998},
  volume = {70},
  pages = {119-134},
  doi = {10.1006/adnd.1998.0788}
}
Abstract: The energy of a level of a specific isotope is affected both by the nuclear motion and the nuclear volume. This program treats the resulting energy shift as a small perturbation that can be separated into the normal and specific mass shift and field shift. Given an electronic wave function, generated either by the MCHF program (LS format) or the MCHF_CI (LSJ format), isotope independent parameters are computed and, from these, shifts between isotopes are predicted. © 1993.
BibTeX:
@article{FischerSmentek-MielczarekVaeckEtAl1993,
  author = {Fischer, C.F. and Smentek-Mielczarek, L. and Vaeck, N. and Miecznik, G.},
  title = {A program to compute isotope shifts in atomic spectra},
  journal = {Computer Physics Communications},
  year = {1993},
  volume = {74},
  pages = {415-431},
  doi = {10.1016/0010-4655(93)90023-6}
}
Abstract: A molecular beam coupled to a Fourier transform spectrometer was used to analyze the rotational structure and vibrational fundamentals of the various propane molecules. Watson type Hamiltonians were used to analyze the two isolated bands while the two higher frequency bands were analyzed using the Coriolis interaction coupling. The standard uncertainties of the values include the calibration errors as well as the the statistical uncertainty of the fittings.
BibTeX:
@article{FlaudLaffertyHerman2001,
  author = {Flaud, J.-M. and Lafferty, W.J. and Herman, M.},
  title = {First high resolution analysis of the absorption spectrum of propane in the 6.7 μm to 7.5 μm spectral region},
  journal = {Journal of Chemical Physics},
  year = {2001},
  volume = {114},
  pages = {9361-9366},
  doi = {10.1063/1.1368386}
}
Abstract: Intercombination line transition rates between n = 2 levels of B II, O V, Ne VII and Mg IX have been calculated using the configuration interaction code CIV3. The recommended A-values for the 2s2p 3P1o-2s2 1S0 intercombination lines are 9.73 s-1 for B II, 2280 s-1 for O V, 19 204 s-1 for Ne VII and 97 242 s-1 for Mg IX. We estimate that the accuracy of these values is better than 2 per cent. Calculations of the M2, E2 and M1 transitions have also been carried out for these ions and for C III.
BibTeX:
@article{FlemingBellHibbertEtAl1996,
  author = {Fleming, J. and Bell, K.L. and Hibbert, A. and Vaeck, N. and Godefroid, M.R.},
  title = {Forbidden transitions in B II, C III, O V, Ne VII and Mg IX},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {1996},
  volume = {279},
  pages = {1289-1293},
  doi = {10.1093/mnras/279.4.1289}
}
Abstract: E1, M2, M1 and E2 rates of transitions between n = 2 levels of N IV have been calculated using the two independent codes CIV3 and MCHF. Convergence of each of the approaches has been studied and comparisons made as the complexity of the calculations increases to include valence, core-valence and core-core correlation. The agreement between the two methods is sufficiently good to allow us to set quite narrow uncertainty bars. For the 1S-1P0 resonance line, our recommended f-value is 0.609 with an estimated uncertainty of 0.002, while our recommended A-value for the 1S0 -3P0 1 intercombination line is 580 s-1 with an estimated uncertainty of 10 s-1.
BibTeX:
@article{FlemingBrageBellEtAl1995,
  author = {Fleming, J. and Brage, T. and Bell, K.L. and Vaeck, N. and Hibbert, A. and Godefroid, M.R. and Froese Fischer, C.},
  title = {Systematic studies of N IV transitions of astrophysical importance},
  journal = {Astrophysical Journal},
  year = {1995},
  volume = {455},
  pages = {758-768},
  doi = {10.1086/176621}
}
Abstract: The oscillator strength of the resonance transition 2s2 1S0-2s2p 1Po1 in neutral beryllium is evaluated using two independent codes: CIV3 and MCHF. Two separate approaches are executed using the code CIV3, which uses a common set of orbitals, the inclusion of valence, core-valence and core-core correlation being approached in different ways. In the MCHF scheme the wavefunctions of the two states are optimized independently. The convergence of the MCHF results with respect to the addition of orbital functions is considered in some detail. This convergence, together with the results of the CIV3 calculates, lead us to recommend a value of 1.375 for the oscillator strength, with an estimated uncertainty of less than 0.5%. This agrees closely with other recent extensive calculations but is 2.5% higher than the value derived from beam-foil experiments.
BibTeX:
@article{FlemingGodefroidBellEtAl1996,
  author = {Fleming, J. and Godefroid, M.R. and Bell, K.L. and Hibbert, A. and Vaeck, N. and Olsen, J. and Jönsson, P. and Froese Fischer, C.},
  title = {The 2s2 1S-2s2p 1Po resonance line in neutral beryllium},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1996},
  volume = {29},
  pages = {4347-4363},
  doi = {10.1088/0953-4075/29/19/009}
}
Abstract: The superposition of configurations (SOC) method has been used to calculate f-values for the Mg H doublet at 1240 Å, which has been observed in the interstellar medium near stars such as ζ Ophiuchi. Our best value for the multiplet oscillator strength is 0.00083. SOC calculations have also been undertaken for the stronger (3s-3p) doublet at 2800 Å giving a multiplet f-value of 0.92.
BibTeX:
@article{FlemingHibbertBellEtAl1998,
  author = {Fleming, J. and Hibbert, A. and Bell, K.L. and Vaeck, N.},
  title = {The 3s 2S-4p 2Po transition probability in Mg II},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {1998},
  volume = {300},
  pages = {767-772},
  doi = {10.1111/j.1365-8711.1998.01935.x}
}
Abstract: Extensive configuration-interaction calculations have been performed to obtain oscillator strengths for the resonance line of the ions of the beryllium isoelectronic sequence up to nuclear charge Z = 12. Valence, corevalence and core-core correlation effects are taken into account and relativistic effects are incorporated using the Breit-Pauli scheme. The present results are believed to be accurate to better than 1%.
BibTeX:
@article{FlemingVaeckHibbertEtAl1996,
  author = {Fleming, J. and Vaeck, N. and Hibbert, A. and Bell, K.L. and Godefroid, M.R.},
  title = {Oscillator strengths for the resonance line of ions in the beryllium isoelectronic sequence},
  journal = {Physica Scripta},
  year = {1996},
  volume = {53},
  pages = {446-453},
  doi = {10.1088/0031-8949/53/4/006}
}
Abstract: The near-infrared emission spectrum of He2, excited in a Be hollow cathode discharge, has been recorded at high resolution using a Fourier transform spectrometer. The c3Σg +-a3Σ u + (0-0, 1-1, 2-2, 1-0, and 2-1) and C1Σg +-A1Σ u + (0-0 and 1-1) transitions have been observed in the 9000-15000 cm spectral region. A global analysis of the six lowest excited states of He2 (C3Σg +, b3IIg, a3Σu +, C1Σg +, B1IIg, and A1Σu +) was carried out by combining our measurements with previously reported infrared data for the b3IIg-a3Σu + system [S. A. Rogers et al., Mol. Phys. 63, 901 (1988)] and with laser measurements for the B1IIg-A1Σu + transition [H. Solka et al., Mol. Phys. 60, 1179 (1987)]. To account for the fine structure in the a3Σu + state, high precision r.f. measurements were included in the global fit. A consistent set of improved molecular constants was derived for the c3Σg + (v = 0, 1, and 2), b3IIg (v = 0 and 1), a3Σu + (v = 0, 1, and 2), C1Σg + (v = 0 and 1), B1IIg (v = 0 and 1), and A1Σu + (v = 0 and 1) levels. A study of the vibrational dependence of these constants was also performed, leading to the equilibrium parameters for the six electronic states. © 1998 Academic Press.
BibTeX:
@article{FocsaBernathColin1998,
  author = {Focsa, C. and Bernath, P.F. and Colin, R.},
  title = {The low-lying states of He2},
  journal = {Journal of Molecular Spectroscopy},
  year = {1998},
  volume = {191},
  pages = {209-214},
  doi = {10.1006/jmsp.1998.7637}
}
Abstract: The A2Π-X2Σ+ Δv = 0 sequence of BeD was observed in the 19 500-20 800 cm-1 spectral region using a Fourier transform spectrometer. The emission spectrum was excited in a Be hollow cathode discharge lamp with a He/D2 gas mixture. The observed lines were assigned to the 0-0 to 6-6 bands. The Δν = -1 sequence was too weak to be seen in our Fourier transform spectra. We therefore used a previously recorded but unpublished arc emission spectrum to identify the 0-1 to 5-6 Δν = -1 bands. Consequently, all of the diagonal bands could be linked together and the vibrational intervals determined. The Δν = 0 and Δν = -1 data were fitted together in a global fit and effective constants derived. Using the information available from the study of the C2Σ+-X2Σ- system [R. Colin, C. Drèze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)], the ν = 8-12 vibrational levels of the ground state were added in a Dunham fit. A set of Dunham Y constants was determined for the X2Σ+ state along with traditional equilibrium parameters for the A2II excited state. The equilibrium bond lengths were found to be 1.341742(5) Å for the ground state and 1.33309(4) Å for the excited state. A reanalysis of the previously published A2Π-X2Σ+ 0-0 to 3-3 Δνv = 0 bands of BeT [D. De Greef and R. Colin, J. Mol. Spectrosc. 53, 455-465 (1974)] was also performed. © 1998 Academic Press.
BibTeX:
@article{FocsaBernathMitznerEtAl1998,
  author = {Focsa, C. and Bernath, P.F. and Mitzner, R. and Colin, R.},
  title = {Fourier Transform Emission Spectroscopy of the A2Π-X2Σ+ Transition of BeD},
  journal = {Journal of Molecular Spectroscopy},
  year = {1998},
  volume = {192},
  pages = {348-358},
  doi = {10.1006/jmsp.1998.7700}
}
Abstract: The A2Π-X2Σ+ transition of BeH was observed by Fourier transform emission spectroscopy using a hollow cathode discharge lamp. The 0-0 to 6-6 bands were rotationally analyzed and molecular constants extracted. The equilibrium rotational constants Be and bond lengths were found to be 10.33121(50) cm-1 and 1.34168(3) Å for the ground state and 10.46631(27) cm-1 and 1.33299(2) Å in the excited state. In order to link the diagonal bands together and to determine the vibrational constants, the 0-1 to 6-7 bands in an archival arc emission spectrum were also rotationally analyzed. In the X2Σ+ and A2Π states, the spectroscopic constants are nearly identical so the Δv=-1 bands were too weak to be seen in our Fourier transform spectra. Franck-Condon factors were calculated for the A2Π-X2Σ+ transition from Rydberg-Klein-Rees potential curves. These new rotational analyses now link up with the previous work on the 0-7, 0-8, 0-9, 1-9 and 1-10 bands of the C2Σ+-X2Σ+ system [R. Colin, C. Drèze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)]. Spectroscopic data are thus available for all bound ground state vibrational levels, v″=0-10, and a set of Dunham Y constants were determined. BeH joins the small group of chemically bound molecules for which a nearly complete set of ground state rovibronic energy levels are known experimentally. © 1998 American Institute of Physics.
BibTeX:
@article{FocsaFirthBernathEtAl1998,
  author = {Focsa, C. and Firth, S. and Bernath, P.F. and Colin, R.},
  title = {Fourier transform emission spectroscopy of the A2Π-X2Σ+ system of BeH},
  journal = {Journal of Chemical Physics},
  year = {1998},
  volume = {109},
  pages = {5795-5802},
  doi = {10.1063/1.477201}
}
Abstract: A very simple circuit for pseudo-tracking of the piezo actuator for continuous-wave cavity ring-down spectroscopy (cw-CRDS) is presented. The circuit is based on an ordinary positive-edge trigger D-type flip flop integrated circuit, has a low parts count, and can be easily assembled using only off the shelf components. The circuit can be straightforwardly incorporated into most cw-CRDS setups and, thanks to the increased ring-down event rate, higher sensitivity or lower data acquisition time can be achieved. © 2013 American Institute of Physics.
BibTeX:
@article{Foeldes2013,
  author = {Földes, T.},
  title = {Note: A very simple circuit for piezo actuator pseudo-tracking for continuous-wave cavity ring-down spectroscopy},
  journal = {Review of Scientific Instruments},
  year = {2013},
  volume = {84},
  article number = {016102},
  doi = {10.1063/1.4774044}
}
Abstract: The absorption spectrum of the (1-0) band of the b1 Σg+ ← a1 Δg Noxon system near 1505 nm has been recorded by cw-CRDS in afterglow of a microwave discharge. The details of this method are presented along with spectroscopic data of 29 recorded lines of which 21 have been observed for the first time. The measured line positions are compared with positions calculated from rotational constants available in the literature. The density and the temperature of the generated singlet molecular oxygen O2 (a1 Δg) are presented. © 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{FoeldesCermakMackoEtAl2009,
  author = {Földes, T. and Čermák, P. and Macko, M. and Veis, P. and Macko, P.},
  title = {Cavity ring-down spectroscopy of singlet oxygen generated in microwave plasma},
  journal = {Chemical Physics Letters},
  year = {2009},
  volume = {467},
  pages = {233-236},
  doi = {10.1016/j.cplett.2008.11.040}
}
Abstract: Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distributed feedback laser module is demonstrated. By adding a compensation waveform current to the step-function switched laser current the laser wavelength stabilisation time is reduced to about 4ms corresponding to a 200Hz utmost ring-down transient repetition rate. © 2010 The Institution of Engineering and Technology.
BibTeX:
@article{FoeldesCermakRakovskyEtAl2010,
  author = {Földes, T. and Čermák, P. and Rakovský, J. and MacKo, M. and Krištof, J. and Veis, P. and MacKo, P.},
  title = {Electronic DFB laser switching for continuous wave cavity ring-down spectroscopy},
  journal = {Electronics Letters},
  year = {2010},
  volume = {46},
  pages = {523-525},
  doi = {10.1049/el.2010.2360}
}
Abstract: Jet-cooled spectra of 14NH3 and 15NH3 in natural abundance were recorded using cavity ring-down (CRDS, 6584-6670 cm-1) and cavity enhanced absorption (CEAS, 6530-6700 cm-1) spectroscopy. Line broadening effects in the CRDS spectrum allowed lines with J'-values between 0 and 3 to be identified. Intensity ratios in 14NH3 between the jet-cooled CRDS and literature room-temperature data from Sung et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1066) further assisted the line assignments. Ground state combination differences were extensively used to support the assignments, providing reliable values for J, K and inversion symmetry of the ground state vibrational levels. CEAS data helped in this respect for the lowest J lines, some of which are saturated in the CRDS spectrum. Further information on a/s doublets arose from the observed spectral structures. Thirty-two transitions of 14NH3 were assigned in this way and a limited but significant number (19) of changes in the assignments results, compared to Sung et al. or to Cacciani et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1084). Sixteen known and 25 new low-J transitions were identified for 15NH3 in the CRDS spectrum but the much scarcer literature information did not allow for any more refined assignment. The present line position measurements improve on literature values published for 15NH3 and on some line positions for 14NH3. © 2014 Taylor & Francis.
BibTeX:
@article{FoeldesGolebiowskiHermanEtAl2014,
  author = {Földes, T. and Golebiowski, D. and Herman, M. and Softley, T.P. and Di Lonardo, G. and Fusina, L.},
  title = {Low-temperature high-resolution absorption spectrum of 14NH3 in the v1+v3 band region (1.51 μm)},
  journal = {Molecular Physics},
  year = {2014},
  volume = {112},
  pages = {2407-2418},
  doi = {10.1080/00268976.2014.904944}
}
Abstract: We have investigated the N2O-HDO molecular complex using ab initio calculations at the CCSD(T)-F12a/aug-cc-pVTZ level of theory and using cavity ring-down spectroscopy to probe an HDO/N2O/Ar supersonic jet around 1.58 m. A single a-type vibrational band was observed, 13 cm-1 redshifted compared to the OH+OD excited band in HDO, and 173 vibration-rotation lines were assigned (Trot ≈ 20 K). A weighted fit of existing microwave and present near infrared (NIR) data was achieved using a standard Watson's Hamiltonian (σ = 1.26), producing ground and excited states rotational constants. The comparison of the former with those calculated ab initio suggests a planar geometry in which the OD rather than the OH bond in water is almost parallel to NNO. The equilibrium geometry and dissociation energy (De = -11.7 kJ/mol) of the water-nitrous oxide complex were calculated. The calculations further demonstrate and allow characterising another minimum, 404 cm-1 (ΔE0) higher in energy. Harmonic vibrational frequencies and dissociation energies, D0, were calculated for various conformers and isotopic forms of the complex, in both minima. The absence of N2O-D2O from dedicated NIR experiments is reported and discussed. © 2014 Taylor & Francis.
BibTeX:
@article{FoeldesLauzinVanfleterenEtAl2015,
  author = {Földes, T. and Lauzin, C. and Vanfleteren, T. and Herman, M. and Liévin, J. and Didriche, K.},
  title = {High-resolution, near-infrared CW-CRDS, and ab initio investigations of N2O-HDO},
  journal = {Molecular Physics},
  year = {2015},
  volume = {113},
  pages = {473-482},
  doi = {10.1080/00268976.2014.953611}
}
Abstract: Cw-CRDS spectra of water-rare gas supersonic expansions were recorded between 7229 and 7262 cm-1. The effective absorption pathlength was about 1 km in jet-cooled gas and the resolution about 1 × 10-4cm-1. Many well-resolved structures are observed that could be assigned from experimental evidence to H2O-Ar/Kr bands. Eight broader unresolved features are more specifically reported and assigned to small H2O multimers, in good agreement and refining previous observations by Nizkorodov et al. [J. Chem. Phys. 122, 194316 (2005)]. Among these, the band at 7256.5 cm-1is shown to be a Q branch of the water dimer with accompanying R and very weak P lines. The band is assigned to a Ka= 0 → 1 transition and rotationally analyzed, leading to a restricted set of upper state rotational constants. The upper state lifetime (60 ± 3 ps) is extracted from the linewidths. © 2014 AIP Publishing LLC.
BibTeX:
@article{FoeldesVanfleterenHerman2014,
  author = {Földes, T. and Vanfleteren, T. and Herman, M.},
  title = {Communication: A rotationally resolved (2OH) overtone band in the water dimer (H2O)2},
  journal = {Journal of Chemical Physics},
  year = {2014},
  volume = {141},
  article number = {111103},
  doi = {10.1063/1.4896163}
}
Abstract: Spectra of 99% isotopically pure 15NH3 were recorded using cavity ring-down (CRD, 6567-6639 cm-1) and Fourier transform (FT, 6350-6985 cm-1) spectroscopy under jet cooled and room temperature conditions, respectively. Measured line positions on both data sets improve on literature values, in particular by one order of magnitude for the ν1+ν3 band. A room temperature list of line positions, with approximate line intensities, is provided, much more complete and precise than presently available. Line broadening effects in the CRD spectrum allowed lines with J'''- values between 0 and 3 to be identified. Ground state combination differences were used to refine the assignments, further assisted by intensity ratios between the two data sets. Reliable values for J, K and inversion symmetry of the ground state vibrational levels, as well as further information on a/s doublets could be obtained, updating and extending literature assignments. © 2016 Elsevier Ltd.
BibTeX:
@article{FoeldesVanfleterenRizopoulosEtAl2016,
  author = {Földes, T. and Vanfleteren, T. and Rizopoulos, A. and Herman, M. and Vander Auwera, J. and Softley, T.P. and Di Lonardo, G. and Fusina, L.},
  title = {High-resolution room temperature and jet-cooled spectroscopic investigation of 1 5NH3 in the ν1+ν3 band region (1.51 μm)},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2016},
  volume = {179},
  pages = {112-125},
  doi = {10.1016/j.jqsrt.2016.03.018}
}
Abstract: Continuous wave (cw) distributed feedback (DFB) telecom diode lasers are increasingly being used as light sources in the near-IR regions of the spectrum for cavity ring-down spectroscopy (CRDS). They are compact, operate economically at room temperature, are able to generate suitable narrowband tunable coherent radiation on a single longitudinal mode and are compatible with a variety of optical components, including fibre-optic devices. The very high sensitivities enabling to measure weak absorption with cw CRDS plus the quantitative nature of the absorption measurements are enabling an expanding range of applications of cw CRDS in molecular spectroscopy, atmospheric chemistry, plasma and medical diagnosis. © 2008 Copyright SPIE - The International Society for Optical Engineering.
BibTeX:
@conference{FoeldesVegsoeCermakEtAl2008,
  author = {Földes, T. and Végsö, K. and Čermák, P. and Veis, P. and Macko, P.},
  title = {Cavity ring-down spectroscopy using telecom diode lasers},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2008},
  volume = {7141},
  article number = {714107},
  doi = {10.1117/12.822352}
}
Abstract: HFC-134a (CF3CH2F) is the most rapidly growing hydrofluorocarbon in terms of atmospheric abundance. It is currently used in a large number of household refrigerators and air-conditioning systems and its concentration in the atmosphere is forecast to increase substantially over the next 50-100 years. Previous estimates of its radiative forcing per unit concentration have differed significantly ∼25%. This paper uses a two-step approach to resolve this discrepancy. In the first step six independent absorption cross section datasets are analysed. We find that, for the integrated cross section in the spectral bands that contribute most to the radiative forcing, the differences between the various datasets are typically smaller than 5% and that the dependence on pressure and temperature is not significant. A "recommended" HFC-134a infrared absorption spectrum was obtained based on the average band intensities of the strongest bands. In the second step, the "recommended" HFC-134a spectrum was used in six different radiative transfer models to calculate the HFC-134a radiative forcing efficiency. The clear-sky instantaneous radiative forcing, using a single global and annual mean profile, differed by 8%, between the 6 models, and the latitudinally-resolved adjusted cloudy sky radiative forcing estimates differed by a similar amount. We calculate that the radiative forcing efficiency of HFC-134a is 0.16 ± 0.02 Wm-2 ppbv-1. © 2004 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ForsterBurkholderClerbauxEtAl2005,
  author = {Forster, P.M.De.F. and Burkholder, J.B. and Clerbaux, C. and Coheur, P.F. and Dutta, M. and Gohar, L.K. and Hurley, M.D. and Myhre, G. and Portmann, R.W. and Shine, K.P. and Wallington, T.J. and Wuebbles, D.},
  title = {Resolution of the uncertainties in the radiative forcing of HFC-134a},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2005},
  volume = {93},
  pages = {447-460},
  doi = {10.1016/j.jqsrt.2004.08.038}
}
Abstract: Between July and November 2008, simultaneous observations were conducted by several orbiting instruments that monitor carbon monoxide in the atmosphere, among them the Infrared Atmospheric Sounding Instrument (IASI) and Measurements Of Pollution In The Troposphere (MOPITT). In this paper, the concentration retrievals at about 700 hPa from these two instruments are successively used in a variational Bayesian system to infer the global distribution of CO emissions. Starting from a global emission budget of 479 Tg for the considered period, the posterior estimate of CO emissions using IASI retrievals gives a total of 643 Tg, which is in close agreement with the budget calculated with version 3 of the MOPITT data (649 Tg). The regional totals are also broadly consistent between the two inversions. Even though our theoretical error budget indicates that IASI constrains the emissions slightly less than MOPITT, because of lesser sensitivity in the lower troposphere, these first results indicate that IASI may play a major role in the quantification of the emissions of CO.
BibTeX:
@article{Fortems-CheineyChevallierPisonEtAl2009,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Carouge, C. and Clerbaux, C. and Coheur, P.-F. and George, M. and Hurtmans, D. and Szopa, S.},
  title = {On the capability of IASI measurements to inform about CO surface emissions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8735-8743},
  doi = {10.5194/acp-9-8735-2009}
}
Abstract: The Measurements of Pollution in the Troposphere (MOPITT) retrievals are used as top-down constraints in an inversion for global CO emissions, for the past 10 years (from March 2000 to December 2009), at 8 day and 3.75° × 2.75° (longitude, latitude) resolution. The method updates a standard prior inventory and yields large increments in terms of annual regional budgets and seasonality. Our validation strategy consists in comparing our posterior-modeled concentrations with several sets of independent measurements: surface measurements, aircraft, and satellite. The posterior emissions, with a global 10 year average of 1430 TgCO/yr, are 37% higher than the prior ones, built from the EDGAR 3.2 and the GFEDv2 inventories (1038 TgCO/yr on average). In addition, they present some significant seasonal variations in the Northern Hemisphere that are not present in our prior nor in others' major inventories. Our results also exhibit some large interannual variability due to biomass burning emissions, climate, and socioeconomic factors; CO emissions range from 1504 TgCO (in 2007) to 1318 TgCO (in 2009). Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Fortems-CheineyChevallierPisonEtAl2011,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Szopa, S. and Deeter, M.N. and Clerbaux, C.},
  title = {Ten years of CO emissions as seen from Measurements of Pollution in the Troposphere (MOPITT)},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D05304},
  doi = {10.1029/2010JD014416}
}
Abstract: Ammonia (NH3), whose main source in the troposphere is agriculture, is an important gaseous precursor of atmospheric particulate matter (PM). We derived daily ammonia emissions using NH3 total columns measured from the Infrared Atmospheric Sounding Interferometer (IASI) on board Metop-A, at a relatively high spatial resolution (grid cell of 0.5° × 0.5°). During the European spring haze episodes of 24–31 March 2012 and 8–15 March 2014, IASI reveals NH3 total column magnitudes highlighting higher NH3 emissions over central Europe (especially over Germany, Czech Republic, and eastern France) from the ones provided by the European reference European Monitoring and Evaluation Programme inventory. These ammonia emissions exhibit in addition a large day-to-day variability, certainly due to spreading practices. The increase of NH3 emissions in the model, that reaches +300% locally, leads to an increase of both NH3 and PM2.5 surface concentrations and allows for a better comparison with independent measurements (in terms of bias, root-mean-square error, and correlation). This study suggests that there are good prospects for better quantifying NH3 emissions by atmospheric inversions. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Fortems-CheineyDufourHamaoui-LaguelEtAl2016,
  author = {Fortems-Cheiney, A. and Dufour, G. and Hamaoui-Laguel, L. and Foret, G. and Siour, G. and Van Damme, M. and Meleux, F. and Coheur, P.-F. and Clerbaux, C. and Clarisse, L. and Favez, O. and Wallasch, M. and Beekmann, M.},
  title = {Unaccounted variability in NH3 agricultural sources detected by IASI contributing to European spring haze episode},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {5475-5482},
  doi = {10.1002/2016GL069361}
}
Abstract: Only very few long-term records of formaldehyde (HCHO) exist that are suitable for trend analysis. Furthermore, many uncertainties remain as to its diurnal cycle, representing a large short-term variability superimposed on seasonal and inter-annual variations that should be accounted for when comparing ground-based observations to, e.g., model results. In this study, we derive a multi-decadal time series (January 1988-June 2015) of HCHO total columns from ground-based high-resolution Fourier transform infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580ma. s. l. ), allowing for the characterization of the mid-latitudinal atmosphere for background conditions. First we investigate the HCHO diurnal variation, peaking around noontime and mainly driven by the intra-day insolation modulation and methane (CH4) oxidation. We also characterize quantitatively the diurnal cycles by adjusting a parametric model to the observations, which links the daytime to the HCHO columns according to the monthly intra-day regimes. It is then employed to scale all the individual FTIR measurements on a given daytime in order to remove the effect of the intra-day modulation for improving the trend determination and the comparison with HCHO columns simulated by the state-of-the-art GEOS-Chem v9-02 chemical transport model. Such a parametric model will be useful to scale the Jungfraujoch HCHO columns on satellite overpass times in the framework of future calibration/validation efforts of space-borne sensors. GEOS-Chem sensitivity tests suggest then that the seasonal and inter-annual HCHO column variations above Jungfraujoch are predominantly led by the atmospheric CH4 oxidation, with a maximum contribution of 25% from the anthropogenic non-methane volatile organic compound precursors during wintertime. Finally, trend analysis of the so-scaled 27-year FTIR time series reveals a long-term evolution of the HCHO columns in the remote troposphere to be related to the atmospheric CH4 fluctuations and the short-term OH variability: +2.9%year-1 between 1988 and 1995, -3.7%year-1 over 1996-2002 and +0.8%year-1 from 2003 onwards. © Author(s) 2016.
BibTeX:
@article{FrancoAMaraisBovyEtAl2016,
  author = {Franco, B. and A Marais, E. and Bovy, B. and Bader, W. and Lejeune, B. and Roland, G. and Servais, C. and Mahieu, E.},
  title = {Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46°N},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {4171-4189},
  doi = {10.5194/acp-16-4171-2016}
}
Abstract: An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580m a.s.l.). The improved spectroscopic parameters include C2H6 pseudo-lines in the 2720-3100cm-1 range and updated line parameters for methyl chloride and ozone. These improved spectroscopic parameters allow for substantial reduction of the fitting residuals as well as enhanced information content. They also contribute to limiting oscillations responsible for ungeophysical negative mixing ratio profiles. This strategy has been successfully applied to the Jungfraujoch solar spectra available from 1994 onwards. The resulting time series is compared with C2H6 total columns simulated by the state-of-the-art chemical transport model GEOS-Chem. Despite very consistent seasonal cycles between both data sets, a negative systematic bias relative to the FTIR observations suggests that C2H6 emissions are underestimated in the current inventories implemented in GEOS-Chem. Finally, C2H6 trends are derived from the FTIR time series, revealing a statistically-significant sharp increase of the C2H6 burden in the remote atmosphere above Jungfraujoch since 2009. Evaluating cause of this change in the C2H6 burden, which may be related to the recent massive growth of shale gas exploitation in North America, is of primary importance for atmospheric composition and air quality in the Northern Hemisphere. © 2015 Elsevier Ltd.
BibTeX:
@article{FrancoBaderToonEtAl2015,
  author = {Franco, B. and Bader, W. and Toon, G.C. and Bray, C. and Perrin, A. and Fischer, E.V. and Sudo, K. and Boone, C.D. and Bovy, B. and Lejeune, B. and Servais, C. and Mahieu, E.},
  title = {Retrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: Recent burden increase above Jungfraujoch},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {160},
  pages = {36-49},
  doi = {10.1016/j.jqsrt.2015.03.017}
}
Abstract: In this study, simulations at 25 km resolution are performed over the Greenland ice sheet (GrIS) throughout the 20th and 21st centuries, using the regional climate model MAR forced by four RCP scenarios from three CMIP5 global circulation models (GCMs), in order to investigate the projected changes of the surface energy balance (SEB) components driving the surface melt. Analysis of 2000-2100 melt anomalies compared to melt results over 1980-1999 reveals an exponential relationship of the GrIS surface melt rate simulated by MAR to the near-surface air temperature (TAS) anomalies, mainly due to the surface albedo positive feedback associated with the extension of bare ice areas in summer. On the GrIS margins, the future melt anomalies are preferentially driven by stronger sensible heat fluxes, induced by enhanced warm air advection over the ice sheet. Over the central dry snow zone, the surface albedo positive feedback induced by the increase in summer melt exceeds the negative feedback of heavier snowfall for TAS anomalies higher than 4 C. In addition to the incoming longwave flux increase associated with the atmosphere warming, GCM-forced MAR simulations project an increase of the cloud cover decreasing the ratio of the incoming shortwave versus longwave radiation and dampening the albedo feedback. However, it should be noted that this trend in the cloud cover is contrary to that simulated by ERA-Interim-forced MAR for recent climate conditions, where the observed melt increase since the 1990s seems mainly to be a consequence of more anticyclonic atmospheric conditions. Finally, no significant change is projected in the length of the melt season, which highlights the importance of solar radiation absorbed by the ice sheet surface in the melt SEB. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX:
@article{FrancoFettweisErpicum2013,
  author = {Franco, B. and Fettweis, X. and Erpicum, M.},
  title = {Future projections of the Greenland ice sheet energy balance driving the surface melt},
  journal = {Cryosphere},
  year = {2013},
  volume = {7},
  pages = {1-18},
  doi = {10.5194/tc-7-1-2013}
}
Abstract: The atmosphere-ocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited AOGCMs for Greenland climate simulation are then selected on the basis of comparison between the 1970-1999 outputs of the Climate of the twentieth Century experiment (20C3M) and reanalyses (ECMWF, NCEP/NCAR). This comparison indicates that the representation quality of surface parameters such as temperature and precipitation are highly correlated to the atmospheric circulation (500 hPa geopotential height) and its interannual variability (North Atlantic oscillation). The outputs of the three most suitable AOGCMs for present-day climate simulation are then used to assess the changes estimated by three IPCC greenhouse gas emissions scenarios (SRES) over the GrIS for the 2070-2099 period. Future atmospheric circulation changes are projected to dampen the zonal flow, enhance the meridional fluxes and therefore provide additional heat and moisture to the GrIS, increasing temperature over the whole ice sheet and precipitation over its northeastern area. We also show that the GrIS surface mass balance anomalies from the SRES A1B scenario amount to -300 km3/year with respect to the 1970-1999 period, leading to a global sea-level rise of 5 cm by the end of the 21st century. This work can help to select the boundaries conditions for AOGCMs-based downscaled future projections. © 2010 Springer-Verlag.
BibTeX:
@article{FrancoFettweisErpicumEtAl2011,
  author = {Franco, B. and Fettweis, X. and Erpicum, M. and Nicolay, S.},
  title = {Present and future climates of the Greenland ice sheet according to the IPCC AR4 models},
  journal = {Climate Dynamics},
  year = {2011},
  volume = {36},
  pages = {1897-1918},
  doi = {10.1007/s00382-010-0779-1}
}
Abstract: With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with decreasing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an "intelligent" interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. © 2013 Author(s).
BibTeX:
@article{FrancoFettweisLangEtAl2012,
  author = {Franco, B. and Fettweis, X. and Lang, C. and Erpicum, M.},
  title = {Impact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990-2010, using the regional climate model MAR},
  journal = {Cryosphere},
  year = {2012},
  volume = {6},
  pages = {695-711},
  doi = {10.5194/tc-6-695-2012}
}
Abstract: As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010&ndash;December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5&deg; N, 8.0&deg; E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6&ndash;8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation. © Author(s) 2015.
BibTeX:
@article{FrancoHendrickVanRoozendaelEtAl2015,
  author = {Franco, B. and Hendrick, F. and Van Roozendael, M. and Müller, J.-F. and Stavrakou, T. and Marais, E.A. and Bovy, B. and Bader, W. and Fayt, C. and Hermans, C. and Lejeune, B. and Pinardi, G. and Servais, C. and Mahieu, E.},
  title = {Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1733-1756},
  doi = {10.5194/amt-8-1733-2015}
}
Abstract: Sharp rises in the atmospheric abundance of ethane (C2H6) have been detected from 2009 onwards in the Northern Hemisphere as a result of the unprecedented growth in the exploitation of shale gas and tight oil reservoirs in North America. Using time series of C2H6 total columns derived from ground-based Fourier transform infrared (FTIR) observations made at five selected Network for the Detection of Atmospheric Composition Change sites, we characterize the recent C2H6 evolution and determine growth rates of ∼5% yr-1 at mid-latitudes and of ∼3% yr-1 at remote sites. Results from CAM-chem simulations with the Hemispheric Transport of Air Pollutants, Phase II bottom-up inventory for anthropogenic emissions are found to greatly underestimate the current C2H6 abundances. Doubling global emissions is required to reconcile the simulations and the observations prior to 2009. We further estimate that North American anthropogenic C2H6 emissions have increased from 1.6 Tg yr-1 in 2008 to 2.8 Tg yr-1 in 2014, i.e. by 75% over these six years. We also completed a second simulation with new top-down emissions of C2H6 from North American oil and gas activities, biofuel consumption and biomass burning, inferred from space-borne observations of methane (CH4) from Greenhouse Gases Observing SATellite. In this simulation, GEOS-Chem is able to reproduce FTIR measurements at the mid-latitudinal sites, underscoring the impact of the North American oil and gas development on the current C2H6 abundance. Finally we estimate that the North American oil and gas emissions of CH4, a major greenhouse gas, grew from 20 to 35 Tg yr-1 over the period 2008-2014, in association with the recent C2H6 rise. © 2016 IOP Publishing Ltd.
BibTeX:
@article{FrancoMahieuEmmonsEtAl2016,
  author = {Franco, B. and Mahieu, E. and Emmons, L.K. and Tzompa-Sosa, Z.A. and Fischer, E.V. and Sudo, K. and Bovy, B. and Conway, S. and Griffin, D. and Hannigan, J.W. and Strong, K. and Walker, K.A.},
  title = {Evaluating ethane and methane emissions associated with the development of oil and natural gas extraction in North America},
  journal = {Environmental Research Letters},
  year = {2016},
  volume = {11},
  article number = {044010},
  doi = {10.1088/1748-9326/11/4/044010}
}
Abstract: Vibrational assignments of fundamental, combination and overtone bands in the main isotopomer of gaseous transformic acid are reported from spectra either newly or previously [J. Chem. Phys. 113 (2000) 1535] recorded using high-resolution Fourier transform and intracavity laser absorption spectroscopies. A total of 62 bands, with 32 newly reported ones, are observed from the lowest energy band, v7 at 626.16 cm-1 up to 4v1 at 13284.1 cm-1. Among these bands, 43 are firmly assigned, and 16 tentatively. Effective vibrational constants are obtained. The normal modes of vibrations are further characterised using ab initio calculations providing fundamental band intensities and picturing normal mode nuclear displacements. The effective investigation of the rotational structure in the first CH stretch overtone band (2v2) and in the second OH stretch overtone band (3v1) is detailed. Rotational information is also presented for 3v2 and two close-lying bands, that could be extracted from the strong overlapping formic acid dimer bands using artificial filtering procedures. © 2002 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{FreytesHurtmansKassiEtAl2002,
  author = {Freytes, M. and Hurtmans, D. and Kassi, S. and Liévin, J. and Vander Auwera, J. and Campargue, A. and Herman, M.},
  title = {Overtone spectroscopy of formic acid},
  journal = {Chemical Physics},
  year = {2002},
  volume = {283},
  pages = {47-61},
  doi = {10.1016/S0301-0104(02)00507-4}
}
Abstract: Recent years have seen a growing number of large-scale atomic structure calculations using both nonrelativistic and relativistic theories. For investigations of multiple and highly charged ions, of course, a relativistic structure code like the widely known GRASP program is required. In a revised version of this program, namely GRASP92 [F.A. Parpia, C.F. Fischer, and I.P. Grant, Comput. Phys. Commun. 94, 249 (1996)], systematic studies of level energies and a few other bound-state properties are now being supported. - Here, we briefly introduce a new package RATIP which extends GRASP92 towards the computation of various Relativistic AtomicTransition and Ionization Properties. A short overview of the capabilities of RATIP along with current developments will be given.
BibTeX:
@conference{FritzscheKoikeSienkiewiczEtAl1999,
  author = {Fritzsche, S. and Koike, F. and Sienkiewicz, J.E. and Vaeck, N.},
  title = {Calculation of relativistic atomic transition and ionization properties for highly-charged ions},
  journal = {Physica Scripta T},
  year = {1999},
  volume = {80},
  pages = {479-481}
}
Abstract: Results from systematic multiconfiguration Hartree-Fock studies of the 2s2 1S0-2s3p 3Po 1 transitions in the Be-like sequence in the range of Z = 4-10 are reported for valence and core-valence models of correlation. The inclusion of core-valence correlation was essential for obtaining good agreement for the fine-structure splitting. The most accurate transition rates are in good agreement with the rates predicted from a semi-empirical analysis of experimental data.
BibTeX:
@article{FroeseFischerGaigalasGodefroid1997,
  author = {Froese Fischer, C. and Gaigalas, G. and Godefroid, M.},
  title = {The 2s2 1S0-2s3p 3P0 1 intercombination line in the Be-like sequence},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1997},
  volume = {30},
  pages = {3333-3342},
  doi = {10.1088/0953-4075/30/15/006}
}
Abstract: Given wave-function expansions for the initial and final state along with expressions for the transition matrix elements, the programs evaluate oscillator strengths and transition probabilities. The MCHF_LSTR program assumes wave functions are represented in the non-relativistic formalism and computers E1 and E2 transition data. The MCHF_LSJTR program requires wave-function expansions from a Breit-Pauli CI calculation and evaluates transition data for E1, E2, ..., or M1, M2, ..., transitions between a series of initial and final states. This program could be used for the study of transitions between multiplets. © 1991.
BibTeX:
@article{FroeseFischerGodefroid1991,
  author = {Froese Fischer, C. and Godefroid, M.R.},
  title = {Programs for computing LS and LSJ transitions from MCHF wave functions},
  journal = {Computer Physics Communications},
  year = {1991},
  volume = {64},
  pages = {501-519},
  doi = {10.1016/0010-4655(91)90141-7}
}
Abstract: Theoretical lifetime trends are reported for all bound singlet states in the n equals 3 complex of the Mg sequence for Z less than equivalent to 26. Calculations are based on MCHF wavefunctions and include only dipole allowed transitions in the LS scheme. For states that are entering the bound spectrum, the reported lifetime is an upper bound. At sufficiently high Z, all these states can decay only through DELTA n equals 0 transitions and several lifetime trends become similar. Implications for the cascade problem in beam-foil spectroscopy are discussed.
BibTeX:
@article{FroeseFischerGodefroid1981,
  author = {Froese Fischer, C. and Godefroid, M.},
  title = {LIFETIME TRENDS FOR THE n equals 3 SINGLET STATES IN THE Mg SEQUENCE.},
  journal = {Nuclear instruments and methods in physics research},
  year = {1981},
  volume = {202},
  pages = {307-322},
  doi = {10.1016/0167-5087(82)90411-2}
}
Abstract: The MCHF_MLTPOL program performs the angular integrations necessary for expressing the matrix elements of transition operators, E1, E2, ..., or M1, M2, ..., as linear combinations of radial integrals. All matrix elements for transitions between two lists of configuration states will be evaluated. A limited amount of non-orthogonality is allowed between orbitals of the initial and final state. © 1991.
BibTeX:
@article{FroeseFischerGodefroidHibbert1991,
  author = {Froese Fischer, C. and Godefroid, M.R. and Hibbert, A.},
  title = {A program for performing angular integrations for transition operators},
  journal = {Computer Physics Communications},
  year = {1991},
  volume = {64},
  pages = {486-500},
  doi = {10.1016/0010-4655(91)90140-G}
}
Abstract: Results from systematic multiconfiguration Hartree-Fock studies of the 2s2 1S-2s3p1Po transition in the Be-like sequence in the range of 7 = 4-10 are reported for several models. The inclusion of core-valence correlation is essential for obtaining good agreement in the length and velocity form of the oscillator strength, the agreement improving with Z and reaching one part in 4000 for neon. In the case of Be, extensive cancellation occurs in the calculation of the dipole matrix element and correlation in the 1s2 core already plays a role at the 1% level of accuracy. The orbitals obtained from the core correlation model were used in a Breit-Pauli calculation mixing 1,3 Po states. The effect on the allowed transition data is included. The present calculations are generally in better agreement with semi-empirical values predicted from experiment than from experiment itself.
BibTeX:
@article{FroeseFischerGodefroidOlsen1997,
  author = {Froese Fischer, C. and Godefroid, M. and Olsen, J.},
  title = {Systematic studies of the 2s2 1S0-2s3p1Po 1 transition in the Be-like sequence},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1997},
  volume = {30},
  pages = {1163-1172},
  doi = {10.1088/0953-4075/30/5/011}
}
Abstract: Some properties of atoms defined in terms of two-electron operators are investigated for sodium. Systematic multiconfiguration Hartree-Fock (MCHF) methods are used. Of particular interest are the energy, the isotope shift parameter, and a dipole-dipole parameter defined as the expectation value of the operator [Formula Presented]. Unlike the one-electron dipole operator, where the line strength was predicted accurately from single, double, and triple excitations, these properties require that quadruple excitations also be considered. © 1998 The American Physical Society.
BibTeX:
@article{FroeseFischerJoenssonGodefroid1998,
  author = {Froese Fischer, C. and Jönsson, P. and Godefroid, M.},
  title = {Some two-electron properties of sodium},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {1998},
  volume = {57},
  pages = {1753-1758},
  doi = {10.1103/PhysRevA.57.1753}
}
Abstract: An MCHF atomic-structure package is presented based on dynamic memory allocation, sparse matrix methods, and a recently developed angular library. It is meant for large-scale calculations in a basis of orthogonal orbitals for groups of LS terms of arbitrary parity. For Breit-Pauli calculations, all operators-spin-orbit, spin-other orbit, spin-spin, and orbit-orbit-may be included. For transition probabilities the orbitals of the initial and final state need not be orthogonal. A bi-orthogonal transformation is used for the evaluation of matrix elements in such cases. In addition to transition rates of all types, isotope shifts and hyperfine constants can be computed as well as gJ factors. New version summary: Title of program: atsp2K. Version number: 1.00. Catalogue identifier: ADLY_v2_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADLY_v2_0. Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland. Computer: Pentium III 500 MHz. Installations: Vanderbilt University, Nashville, TN 37235, USA. Operating systems under which the present version has been tested: Red Hat 8. Programming language used in the present version: FORTRAN 90. Memory required to execute with typical data: 256 Mbytes words. No. of bits in a word: 32. Supplementary material: User manuals for the program atsp2k and for the Spin-Angular library are available. No. of lines in distributed program, including test data, etc.:209 992. No. of bytes in distributed package, including test data, etc.: 1 740 883. Distribution format: tar.gz. CPC Program Library subprograms used: none. Does the new version supersede the previous version?: Yes. Nature of physical problem: This program determines energy levels and associated wave functions for states of atoms and ions in the MCHF (LS) or Breit-Pauli (LSJ) approximation. Given the wave function, various atomic properties can be computed such as electric (Ek) and magnetic (Mk) multipole radiative transition probabilities (kmax = 10) between LS or LSJ states, isotope shift constants, hyperfine parameters, and gJ factors. Method of solution: The new version of the program closely follows the design and structure of the previous one [C. Froese Fischer, Comput. Phys. Comm. 128 (2000) 635], except that a simultaneous optimization scheme has been introduced. This program uses the angular methodology of [G. Gaigalas, Lithuanian J. Phys. 41 (2000) 39] and has been extended to include partially filled f-subshells in wavefunction expansions but assumes all orbitals are orthonormal. The bi-orthogonal transformation method is used to deal with the non-orthogonality of orbitals between initial and final states of an electromagnetic radiative transition. Reasons for new version: The previous version of the MCHF atomic structure package [C. Froese Fischer, Comput. Phys. Comm. 128 (2000) 635] was intended for small calculations, ideal for someone not familiar with the code, producing extensive print-out of intermediate results. The codes for the calculation of spin-angular coefficients were often not the most efficient and could only treat configurations with open f-subshells containing at most two electrons or an almost filled shell with one hole. The present version is designed for large-scale computation using algorithms for angular integration that have been shown to be faster, and include the case of arbitrarily filled f-shells. In addition, the MCHF program has been modified to include optimization on an energy functional that is a weighted average of energy functionals for expansions of wavefunctions for different LS terms or parity, thus facilitating Breit-Pauli calculations for complex atomic systems and for computing targets in collision calculations. Summary of revisions: Programs have been modified to take advantage of the newly developed angular library [G. Gaigalas, Lithuanian J. Phys. 41 (2000) 39], extended to arbitrarily filled f-shells. New programs have been developed for simultaneous optimization and for the efficient calculation of atomic spectra and transition rates for an iso-electronic sequence. All applications now take advantage of dynamic memory allocation and sparse matrix methods. Restrictions on the complexity of the problem: All orbitals in a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight (8) subshells in addition to the closed shells common to all configuration states. The maximum size is limited by the available memory and disk space. Typical running time: Included with the code are scripts for calculating E2 and M1 transitions between levels of 3 s2 3 p2 for Si and P+. This calculation has two stages: LS and LSJ. The calculation of the former required 21 minutes for the LS calculation and 36.5 minutes for the Breit-Pauli configuration interaction calculation that determines the mixing of the terms. Unusual features of the program: The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade but their implementations are compiler dependent. The present serial code has been installed and tested extensively using both the Portland Group, pgf90, compiler and the IBM SP2, xlf90, compiler. The former is compatible also with the Intel Fortran90 compiler. The MPI codes are included for completeness though testing has not been as extensive. Additional comments: Parallel versions (MPI) of the following programs are included in the distribution. Use of these is optional but can speed up the angular integration processing. A table is presented. © 2007 Elsevier B.V. All rights reserved.
BibTeX:
@article{FroeseFischerTachievGaigalasEtAl2007,
  author = {Froese Fischer, C. and Tachiev, G. and Gaigalas, G. and Godefroid, M.R.},
  title = {An MCHF atomic-structure package for large-scale calculations},
  journal = {Computer Physics Communications},
  year = {2007},
  volume = {176},
  pages = {559-579},
  doi = {10.1016/j.cpc.2007.01.006}
}
Abstract: No lines have been observed for transitions between the doublet and quartet levels of B i. Consequently, energy levels based on observation for the latter are obtained through extrapolation of wavelengths along the isoelectronic sequence for the 2s22p 2P3/2o - 2s2p2 4P5/2 transition. In this paper, accurate theoretical excitation energies from a partitioned-correlation- function-interaction (PCFI) method are reported for B i that include both relativistic effects in the Breit-Pauli approximation and a finite mass correction. Results are compared with extrapolated values from observed data. For B i our estimate of the excitation energy 28 959 ± 5 cm-1 is in better agreement with the values obtained by Edlén (1969) than those reported by Kramida and Ryabtsev (2007). Our method is validated by applying the same procedure to the separation of these levels in C ii. © 2013 American Physical Society.
BibTeX:
@article{FroeseFischerVerdeboutGodefroidEtAl2013,
  author = {Froese Fischer, C. and Verdebout, S. and Godefroid, M. and Rynkun, P. and Jönsson, P. and Gaigalas, G.},
  title = {Doublet-quartet energy separation in boron: A partitioned-correlation- function-interaction method},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2013},
  volume = {88},
  article number = {062506},
  doi = {10.1103/PhysRevA.88.062506}
}
Abstract: First-principles dynamics simulations (DFT, PBE96, and PBE0) and electron scattering calculations (FEFF9) provide near-quantitative agreement with new and existing XAFS measurements for a series of transition-metal ions interacting with their hydration shells via complex mechanisms (high spin, covalency, charge transfer, etc.). This analysis does not require either the development of empirical interparticle interaction potentials or structural models of hydration. However, it provides consistent parameter-free analysis and improved agreement with the higher-R scattering region (first- and second-shell structure, symmetry, dynamic disorder, and multiple scattering) for this comprehensive series of ions. DFT+GGA MD methods provide a high level of agreement. However, improvements are observed when exact exchange is included. Higher accuracy in the pseudopotential description of the atomic potential, including core polarization and reducing core radii, was necessary for very detailed agreement. The first-principles nature of this approach supports its application to more complex systems. © 2012 American Chemical Society.
BibTeX:
@article{FultonBylaskaBogatkoEtAl2012,
  author = {Fulton, J.L. and Bylaska, E.J. and Bogatko, S. and Balasubramanian, M. and Cauët, E. and Schenter, G.K. and Weare, J.H.},
  title = {Near-quantitative agreement of model-free DFT-MD predictions with XAFS observations of the hydration structure of highly charged transition-metal ions},
  journal = {Journal of Physical Chemistry Letters},
  year = {2012},
  volume = {3},
  pages = {2588-2593},
  doi = {10.1021/jz3008497}
}
Abstract: The vibrational fundamentals and the rotational levels up to J=7 of the X̃3B1 and ã1A1 electronic states of CH2 have been computed completely ab initio. The calculations were based on converged, variational nuclear motion calculations employing high-quality ab initio quartic force field approximations of the related potential energy surfaces (PES). The vibrational fundamentals obtained are compared to other computational results, namely those obtained from second-order vibrational perturbation theory (VPT2) and the nonrigid-rotation- large-amplitude-internal-motion Hamiltonian (NRLH) approach. The variationally computed rotational transitions are compared both to experimentally available results and to results obtained using empirical, fitted PESs. The comparisons suggest that while the fitted PESs of X̃3B1 CH 2 reproduce excellently the available rovibrational transition wavenumbers, the corresponding stretching fundamental term values, which have not been determined experimentally, are less accurate than the ab initio values obtained in the present study. This means that the zero-point energy (ZPE) computed ab initio in the present work is an improvement over that computed from the fitted PES of X̃3B1 CH2. No similar problems are observed for the semirigid ã1A1 state of CH2, where the computed, the fitted, and the experimental results all agree with each other. The symmetric and antisymmetric stretching fundamentals of X̃3B1 CH2 obtained in this study are 3035±7 and 3249±7 cm-1, respectively. The corresponding ZPE of X̃3B1 is 3733±10 cm -1, while that of ã1A1 CH2 is 3605±15 cm-1. © 2005 Elsevier B.V. All rights reserved.
BibTeX:
@article{FurtenbacherCzakoSutcliffeEtAl2006,
  author = {Furtenbacher, T. and Czakó, G. and Sutcliffe, B.T. and Császár, A.G. and Szalay, V.},
  title = {The methylene saga continues: Stretching fundamentals and zero-point energy of X̃3 B1 CH2},
  journal = {Journal of Molecular Structure},
  year = {2006},
  volume = {780-781},
  pages = {283-294},
  doi = {10.1016/j.molstruc.2005.06.052}
}
Abstract: The high resolution spectrum of 15NH3 has been recorded at unapodized resolution of 0.00096 cm−1 in the region 60–600 cm−1 using the Bruker IFS 125 Fourier transform spectrometer located at the far-infrared beam-line, Canadian Light Source. We report on the observation and analysis of the rotation-inversion spectrum in the ground, v2=1, 2 and v4=1 states. All the rotation-inversion transitions in the ground state together with the pure inversion transitions present in the literature were fitted simultaneously on the basis of a rotation-inversion Hamiltonian which includes distortion constants up to the 12th power in the angular momentum and the Δk=±3 and Δk=±6 interaction terms. A set of effective parameters was also obtained for the v2=1 state adopting the same theoretical model. For the v2=2 and v4=1 states only a list of observed transitions is reported. The wavenumbers of all the assigned transitions were compared with their theoretically predicted values [S.N. Yurchenko, J. Quant. Spectrosc. Radiat. Transf., 2015, 152, 28]. The present results noticeably improve the wavenumber line list in the HITRAN data base [L. S. Rothman et al. J. Quant. Spectrosc. Radiat. Transf.,2013, 130, 4]. © 2017 Elsevier Ltd
BibTeX:
@article{FusinaDiLonardoCaneEtAl2017,
  author = {Fusina, L. and Di Lonardo, G. and Canè, E. and Predoi-Cross, A. and Rozario, H. and Herman, M.},
  title = {The high resolution spectrum of 15NH3 in the far-infrared: Rotation-inversion transitions in the ground, v2=1, 2 and v4=1 states},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {203},
  pages = {417-424},
  doi = {10.1016/j.jqsrt.2017.01.021}
}
Abstract: The autoionizing spectrum of Ca has been studied in the wavelength ranges of 490-540 nm and 555-590 nm through multiphoton absorption and the subsequent decay to excited Ca+(4p2P3/2, 1/2) states. The fluorescence signal of Ca+(4p) exhibits resonances attributed to the 3d6p and 3dnf (n=4-7) doubly excited autoionizing 3 = 1, 3 states (three-photon absorption) together with resonances due to excited bound states (two- photon absorption) of the neutral atom. Sufficient atomic density was obtained utilizing a vapour in a moderate pressure regime (2-5 mTorr) such that collisional excitation was stilt negligible. The pulsed ~-8 ns duration (fwhm) laser radiation was used in linear as well as in circular polarization. The observed 3 = 3 states has been interpreted with the help of theoretical results obtained by a configuration interaction approach. © 1991 IOP Publishing Ltd.
BibTeX:
@article{GaardstedAndersentHaugenEtAl1991,
  author = {Gaardsted, J.O. and Andersent, T. and Haugen, H.K. and Hansen, J.E. and Vaeck, N.},
  title = {Multiphoton spectroscopy of doubly excited autoionizing states of ca},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1991},
  volume = {24},
  pages = {4363-4377},
  doi = {10.1088/0953-4075/24/20/008}
}
Abstract: The density of U atoms in the (5L06) ground state present in a vapor of this element from a hollow cathode lamp has been measured using laser absorption spectroscopy.The influence of the carrier gases (Ar, Kr, Xe) on the density, the absorption coefficient profiles, and on the ratio of U atoms to the dissipated electrical power has been investigated.It has been found that, in our range of operating conditions, the xenon gas is the most efficient.With xenon, a density of 2.2 × 1012 cm−3 ground-state U atoms is obtained when the lamp dissipates 40 W of electrical power.© 1979 Optical Society of America.
BibTeX:
@article{GagneLeblancMongeauEtAl1979,
  author = {Gagné, J.M. and Leblanc, B. and Mongeau, B. and Carleer, M. and Bertrand, L.},
  title = {Study by absorbing a vapor of a laser beam d'238 U(5L06) obtained using a hollow cathode lamp},
  journal = {Applied Optics},
  year = {1979},
  volume = {18},
  pages = {1084-1087},
  doi = {10.1364/AO.18.001084}
}
Abstract: The production of uranium vapors has been studied in the 5L°6 ground state using a pulsed hollow cathode lamp. The evolution of the 238U (5L°6) concentration with time has been studied with Xe and Ar as buffer gases. A density of 2.7 × 1013 atoms cm-3 was obtained with Xe as a buffer gas. In addition, those measurements, obtained from the absorption of a laser beam tuned to the 5758.143 Å (5L°6-17, 3617L6) transition, lowed the determination of the transition probability A = 2.1 × 105 sec-1 and of the branching ratio BR = 0.08 for this transition. © 1979 Optical Society of America.
BibTeX:
@article{GagneCarleerLeblancEtAl1979,
  author = {Gagné, J.-M. and Carleer, M. and Leblanc, B. and Demers, Y. and Mongeau, B.},
  title = {Générateur de vapeur d’uranium: La lampe à cathode creuse pulsée},
  journal = {Applied Optics},
  year = {1979},
  volume = {18},
  pages = {2107-2111},
  doi = {10.1364/AO.18.002107}
}
Abstract: Within the lowest-order relativistic approximation (∼v 2/c2) and to first order in me/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac-Hartree-Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. This work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for obtaining reliable isotope shift values. © 2011 IOP Publishing Ltd.
BibTeX:
@article{GaidamauskasNazeRynkunEtAl2011,
  author = {Gaidamauskas, E. and Nazé, C. and Rynkun, P. and Gaigalas, G. and Jönsson, P. and Godefroid, M.},
  title = {Tensorial form and matrix elements of the relativistic nuclear recoil operator},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2011},
  volume = {44},
  article number = {175003},
  doi = {10.1088/0953-4075/44/17/175003}
}
Abstract: Chemical beam epitaxy (CBE) is demonstrated here to be a suitable technique for the planarization of etched structures by selective overgrowth of InP layers. We present the fabrication of planar buried heterostructure laser diodes (PBH-LDs) with a separate confinement multiquantum well active layer grown by gas source molecular beam epitaxy and p-n InP current blocking layers grown by CBE. These lasers have been operated cw showing threshold current as low as 17 mA and maximum power up to 25 mW. We also achieved for the first time the fabrication of PBH-LD using molecular beam epitaxy techniques only.
BibTeX:
@article{GailhanouLabourieLievinEtAl1991,
  author = {Gailhanou, M. and Labourie, C. and Liévin, J.L. and Perales, A. and Lambert, M. and Poingt, F. and Sigogne, D.},
  title = {Chemical beam epitaxial selective growth of InP for laser fabrication},
  journal = {Applied Physics Letters},
  year = {1991},
  volume = {58},
  pages = {796-798},
  doi = {10.1063/1.104519}
}
Abstract: Ab initio multiconfiguration Dirac–Hartree–Fock (MCDHF) calculations have been carried out in order to determine the isotope shift (IS) electronic parameters of transitions belonging to electric dipole (E1) transition arrays 5s25p3−5s25p26s, 5s25p26s−5s25p26p and 5s25p26s−5s25p27p in neutral antimony, Sb I. In a correlation model limited to single and double excitations from the valence shells, these parameters, combined with the changes in mean-square nuclear charge radius δ⟨r2⟩123,121 compiled by Angeli and Marinova [3] produce isotope shifts values in good agreement with the most recent measurements by high-resolution emission and optogalvanic absorption spectroscopy of Sobolewski et al. [5] but not with the old measurements of Buchholz et al. [4] for 5p3−5p26s. However, our analysis does not allow to reject the latter due to the large uncertainty affecting δ⟨r2⟩123,121, i.e. 0.072 ± 0.048 fm2 [3]. This shows the need of a more accurate determination of this nuclear parameter. Although improving excitation energies, the inclusion of core-valence correlation limited to one hole in the 4d core subshell destroyed the theory-experiment agreement on the IS parameters. © 2018 Elsevier Ltd
BibTeX:
@article{GamrathPalmeriQuinetEtAl2018,
  author = {Gamrath, S. and Palmeri, P. and Quinet, P. and Bouazza, S. and Godefroid, M.},
  title = {MCDHF calculations of isotope shifts in neutral antimony},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2018},
  volume = {218},
  pages = {38-45},
  doi = {10.1016/j.jqsrt.2018.07.004}
}
Abstract: High-spectral resolution infrared spectra of the earth's atmosphere and surface are routinely available from satellite sensors, such as the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI). We exploit the spectral content of AIRS data to demonstrate that airborne volcanic ash has a unique signature in the infrared (8-12 μm) that can be used to infer particle size, infrared opacity and composition. The spectral signature is interpreted with the aid of a radiative transfer model utilizing the optical properties of andesite, rhyolite and quartz. Based on the infrared spectral signature, a new volcanic ash detection algorithm is proposed that can discriminate volcanic ash from other airborne substances and we show that the algorithm depends on particle size, optical depth and composition. The new algorithm has an improved sensitivity to optically thin ash clouds, and hence can detect them for longer (~ 4 days) and at greater distances from the source(~ 5000 km). © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{GangalePrataClarisse2010,
  author = {Gangale, G. and Prata, A.J. and Clarisse, L.},
  title = {The infrared spectral signature of volcanic ash determined from high-spectral resolution satellite measurements},
  journal = {Remote Sensing of Environment},
  year = {2010},
  volume = {114},
  pages = {414-425},
  doi = {10.1016/j.rse.2009.09.007}
}
Abstract: Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their vertical sensitivity with ozonesonde measurements. In this paper, ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the polar-orbiting satellite MetOp are compared with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi measurement campaign. The main objective of the campaign was the satellite data validation. With this aim 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because the balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria vary according to the availability of global positioning system auxiliary data with each electro-chemical cell ozonesonde observation. The relative mean difference is shown to depend on the vertical range investigated. The analysis shows a good agreement in the troposphere (below 10 km) and middle stratosphere (25-40 km), where the differences are lower than 10%. However a significant positive bias of about 10-26% is estimated in the lower stratosphere at 10-25 km, depending on altitude. The positive bias in the 10-25 km range is consistent with previously reported studies comparing in situ data with thermal infrared satellite measurements. This study allows for a better characterization of IASI-retrieved ozone over the polar region during ozone depletion/recovery processes. © Author(s) 2013.
BibTeX:
@article{GazeauxClerbauxGeorgeEtAl2013,
  author = {Gazeaux, J. and Clerbaux, C. and George, M. and Hadji-Lazaro, J. and Kuttippurath, J. and Coheur, P.-F. and Hurtmans, D. and Deshler, T. and Kovilakam, M. and Campbell, P. and Guidard, V. and Rabier, F. and Thépaut, J.-N.},
  title = {Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {613-620},
  doi = {10.5194/amt-6-613-2013}
}
Abstract: Carbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another 15 and more years of observations will be provided by the IASI/MetOp instrument series (2007-2023 >). In order to study long-term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved quantities are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a 6-year overlap period (2008-2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms (v5T for MOPITT and v20100815 for IASI), and second using a dedicated reprocessing of MOPITT CO profiles and columns using the same a priori information as the IASI product. MOPITT total columns are generally slightly higher over land (bias ranging from 0 to 13 %) than IASI data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15 %) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to a larger variability associated with the a priori. © 2015 Author(s).
BibTeX:
@article{GeorgeClerbauxBouararEtAl2015,
  author = {George, M. and Clerbaux, C. and Bouarar, I. and Coheur, P.-F. and Deeter, M.N. and Edwards, D.P. and Francis, G. and Gille, J.C. and Hadji-Lazaro, J. and Hurtmans, D. and Inness, A. and Mao, D. and Worden, H.M.},
  title = {An examination of the long-term CO records from MOPITT and IASI: Comparison of retrieval methodology},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {4313-4328},
  doi = {10.5194/amt-8-4313-2015}
}
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp satellite measures carbon monoxide (CO) on a global scale, twice a day. CO total columns and vertical profiles are retrieved in near real time from the nadir radiance spectra measured by the instrument in the thermal infrared (TIR) spectral range. This paper describes the measurement vertical sensitivity and provides a first assessment of the capabilities of IASI to measure CO distributions. On the global scale, 0.8 to 2.4 independent pieces of information are available for the retrieval. At mid latitudes, the information ranges between 1.5 and 2, which enables the lower and upper troposphere to be distinguished, especially when thermal contrast is significant. Global distributions of column CO are evaluated with correlative observations available from other nadir looking TIR missions currently in operation: the Measurements of Pollution in the Troposphere (MOPITT) onboard TERRA, the Atmospheric Infrared Sounder (AIRS) onboard AQUA and the Tropospheric Emission Spectrometer (TES) onboard AURA. The IASI CO columns are compared with MOPITT, AIRS and TES CO columns, adjusted with the a priori, for three different months: August 2008, November 2008 and February 2009. On average, total column discrepancies of about 7% are found between IASI and the three other sounders in the Northern Hemisphere and in the equatorial region. However when strong CO concentrations are present, such as during fire events, these discrepancies can climb as high as 17%. Instrument specifications of IASI versus other missions are also discussed.
BibTeX:
@article{GeorgeClerbauxHurtmansEtAl2009,
  author = {George, M. and Clerbaux, C. and Hurtmans, D. and Turquety, S. and Coheur, P.-F. and Pommier, M. and Hadji-Lazaro, J. and Edwards, D.P. and Worden, H. and Luo, M. and Rinsland, C. and McMillan, W.},
  title = {Carbon monoxide distributions from the IASI/METOP mission: Evaluation with other space-borne remote sensors},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8317-8330},
  doi = {10.5194/acp-9-8317-2009}
}
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled overtone absorption spectrum of 12C2H4 between 3800 cm−1 and 7900 cm−1, at a spectral resolution of 0·02 cm−1. The experimental set-up and its technical performance are described. The spectral data are exemplified with the help of six selected bands, at 4288·40, 4312·63, 4321·77, 4328·65, 4514·657 and 6150·978 cm−1, whose rotational analysis is performed for the first time. The two lower energy bands, both b type, were not previously reported at all. They are tentatively assigned to the anharmonically resonant pair υ2 + υ6 + υ12 and υ6 + 2υ10 + υ12. © 1997 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{GeorgesBachHerman1997,
  author = {Georges, B.R. and Bach, M. and Herman, M.},
  title = {High resolution FTIR spectroscopy using a slit jet: Sampling the overtone spectrum of 12C2H4},
  journal = {Molecular Physics},
  year = {1997},
  volume = {90},
  pages = {381-388},
  doi = {10.1080/002689797172499}
}
Abstract: All known vibrational energies in 12C2H4([Xtilde]1 Ag) are collected. A block-diagonalized vibrational matrix Hamiltonian is set up, combining a Dunham expansion with the 2/10,10, 11/2,12, and the 5,5/9,9, 1,1/11,11,1,9/5,11 and 1,11/5,9 anharmonic resonances, with the normal modes numbered according to the most usual conventions in the previous literature. A step by step fitting procedure is applied. Vibrational constants are obtained, and vibrational assignments are provided and discussed. A slightly modified ensemble of vibrational constants is also produced by taking care of a more extended set of resonances between the CH-type vibrations. A new constant of the motion N = 3ν1 + 3ν5 + 3ν9 + 3ν11 + 2ν2 + ν10 + ν12 is demonstrated to support the latter vibrational energy pattern. © 1999 Taylor &amp; Francis Group, LLC.
BibTeX:
@article{GeorgesBachHerman1999,
  author = {Georges, R. and Bach, M. and Herman, M.},
  title = {The vibrational energy pattern in ethylene (12C2H4)},
  journal = {Molecular Physics},
  year = {1999},
  volume = {97},
  pages = {279-292},
  doi = {10.1080/00268979909482829}
}
Abstract: A new supersonic expansion made of several, up to 31 aligned nozzles, on top of a set of powerful Roots blowers has been built. Adequate optics allowed the recording of infrared absorption spectra in a cell with a Fourier transform interferometer, at high spectral resolution. The system was tested with N2O, between 2000 and 4800 cm-1. The ν1 + 2ν2 + ν3 combination band, estimated to be some 10000 times weaker than the ν2 fundamental, could be observed among all the other expected bands, thus setting a limit for the sensitivity of the system. The formation of large N2O clusters was observed. © 1995.
BibTeX:
@article{GeorgesDurryBachEtAl1995,
  author = {Georges, R. and Durry, G. and Bach, M. and Pétrisse, R. and Jost, R. and Herman, M.},
  title = {Multinozzle supersonic expansion for Fourier transform absorption spectroscopy},
  journal = {Chemical Physics Letters},
  year = {1995},
  volume = {246},
  pages = {601-606},
  doi = {10.1016/0009-2614(95)01161-4}
}
Abstract: Room temperature absorption spectra of the gaseous (C2h) dimer of formic acid were recorded from the lowest energy fundamental, ν16, with origin at 69.2 cm-1, up to the CH overtone bands with Δv=4, with origin at 11,103 cm-1, using a high resolution Fourier transform interferometer. These spectra are complemented with liquid phase data in the NIR region. In addition, jet-cooled spectra were recorded over the range 1850-3750 cm-1. The origin of the many observed bands is listed, together with relative intensities for those recorded under jet-cooled conditions. Systematic problems encountered with vibrational assignments for bands other than fundamentals are highlighted and, as a rule, left unsolved except for the bands at 167.26 and 2586.34 cm-1 tentatively assigned to ν15+ν16-ν16 and ν5+ν22 or ν6+ν21, respectively. For the first, FIR band the assignment is supported by partly unravelling the hot band pattern around ν15 at 168.47 cm -1. The jet-cooled rotational contour of the second, MIR band was simulated, allowing the rotational temperature in the jet to be estimated to 35 K. © 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{GeorgesFreytesHurtmansEtAl2004,
  author = {Georges, R. and Freytes, M. and Hurtmans, D. and Kleiner, I. and Vander Auwera, J. and Herman, M.},
  title = {Jet-cooled and room temperature FTIR spectra of the dimer of formic acid in the gas phase},
  journal = {Chemical Physics},
  year = {2004},
  volume = {305},
  pages = {187-196},
  doi = {10.1016/j.chemphys.2004.06.027}
}
Abstract: We have recorded high-resolution absorption spectra of 12CH4 cooled in ajet, using a Fourier transform interferometer. The expected nuclear spin symmetry conservation in the jet is exhibited from data recorded around 3000 cm-1 showing the relative intensity of the lines starting from the J″ = 2 para and ortho levels. Spectra recorded around 4300 cm-1 are used to validate existing rovibrational parameters. Spectra recorded around 6000 cm-1 allow new rovibrational assignments to be performed in the N = 4 polyad. In particular, lines in the V1 + V3 band are identified for the first time. © 1998 Academic Press.
BibTeX:
@article{GeorgesHermanHilicoEtAl1998,
  author = {Georges, R. and Herman, M. and Hilico, J.-C. and Robert, O.},
  title = {High-resolution FTIR spectroscopy using a jet: Sampling the rovibrational spectrum of 12CH4},
  journal = {Journal of Molecular Spectroscopy},
  year = {1998},
  volume = {187},
  pages = {13-20},
  doi = {10.1006/jmsp.1997.7462}
}
Abstract: The v1 fundamental band in N2O3 was recorded in absorption at high spectral resolution with a Fourier Transform interferometer, under jet cooled experimental conditions. The rotational structure, corresponding to 44 K rotational temperature, could be analysed, leading to a set of precise upper state parameters. The absence of b-type lines in the spectrum, expected to occur from the direction of the Q1 normal coordinate with respect to the principal axes of inertia, is fully justified by ab initio calculations performed at the MP2/6-31G * level, confirming the decisive role of the polarizing NO2 chromophore in tilting the corresponding induced dipole moment towards the direction of the a axis. The calculations also provide equilibrium geometry parameters.
BibTeX:
@article{GeorgesLievinHermanEtAl1996,
  author = {Georges, R. and Liévin, J. and Herman, M. and Perrin, A.},
  title = {The v1 band in N2O3},
  journal = {Chemical Physics Letters},
  year = {1996},
  volume = {256},
  pages = {675-678},
  doi = {10.1016/0009-2614(96)00510-6}
}
BibTeX:
@article{GeorgesVanDerVorstHermanEtAl1997,
  author = {Georges, R. and Van Der Vorst, D. and Herman, M. and Hurtmans, D.},
  title = {Ar and Self-Pressure Broadening Coefficient of the R(11), 5v3 Line of 12C2H2},
  journal = {Journal of Molecular Spectroscopy},
  year = {1997},
  volume = {185},
  pages = {187-188},
  doi = {10.1006/jmsp.1997.7372}
}
Abstract: Three simplifying methodds are discussed and applied to the four lowest valence states of CH2(3B1, 1A1, 1B1 and 1Σ g+(1A 1*)) and to the two lowest of CH 2+(2A1 and 2∏u(2B1)). These methods concern: (1) the development of polarization functions for Gaussian‐lobe basis sets by least‐square fitting of numebrical multiconfigurational atomic fuinctions (this approach is tested also on (C2H2, (2) the use of intermediate Hamiltonians to calculate avoided crossings between potential hypersurfaces, and (3) thecalculation of correlation energies using an atoms‐in‐molecule approach. The calculated equilibrium geometries of the CH2 States are within 0.02 Å and 5° of available experimental data. The calculated term values and ionization potentials, Te(1A1 = 0.35 eV, Te (1B1) = 1.22 eV, Te (1Σ g+(1A 1*)) 2.48 eV, I.P. (2A1) = 10.39 eV and I. P. (2∏u(2B1)) = 10.58 eV, are in agreement with some recent theoretical studies, and are very close to existing experimental information. Copyright © 1977 John Wiley &amp; Sons, Inc.
BibTeX:
@article{GervyVerhaegen1977,
  author = {Gervy, D. and Verhaegen, G.},
  title = {Simplified methods for ab initio calculations. The valence states of CH2 and CH 2+},
  journal = {International Journal of Quantum Chemistry},
  year = {1977},
  volume = {12},
  pages = {115-131},
  doi = {10.1002/qua.560120111}
}
BibTeX:
@article{GilbertHansonNormanEtAl1966,
  author = {Gilbert, B.C. and Hanson, P. and Norman, R.O.C. and Sutcliffe, B.T.},
  title = {The cation-radical and the neutral radical from phenothiazine},
  journal = {Chemical Communications (London)},
  year = {1966},
  pages = {161-164},
  doi = {10.1039/C19660000161}
}
Abstract: The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH 3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH 3, with only 1% difference between land-use databases. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH 3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH 3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m 2 g -1 as NH 3 burden increases from 0 to 40 mg m -2. The fine mode extinction efficiency, ranging from 4 to 16 m 2 g -1, does not appear to depend on NH 3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties. © 2012 Author(s).
BibTeX:
@article{GinouxClarisseClerbauxEtAl2012,
  author = {Ginoux, P. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dubovik, O. and Hsu, N.C. and Van Damme, M.},
  title = {Mixing of dust and NH 3 observed globally over anthropogenic dust sources},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {7351-7363},
  doi = {10.5194/acp-12-7351-2012}
}
Abstract: Relations between magnetic radial integrals are derived and used in the discussion of symmetry properties of mutual spin-orbit matrix elements.
BibTeX:
@article{Godefroid1982,
  author = {Godefroid, M.},
  title = {Note on the mutual spin-orbit matrix elements},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1982},
  volume = {15},
  article number = {008},
  pages = {3583-3586},
  doi = {10.1088/0022-3700/15/20/008}
}
BibTeX:
@article{Godefroid1978,
  author = {Godefroid, M.},
  title = {An adaptation of acrz to calculate electric quadrupole oscillator strengths},
  journal = {Computer Physics Communications},
  year = {1978},
  volume = {15},
  pages = {275-282},
  doi = {10.1016/0010-4655(78)90097-8}
}
Abstract: Transition state Hamiltonians are used at a multiconflgurational level of accuracy to calculate the oscillator strength (length and velocity forms) of the 1s22s2(1S) → 1s22s2p(1P0) transition of beryllium. Three distinct approximations of the formalism are developed and examined. Copyright © 1977 John Wiley &amp; Sons, Inc.
BibTeX:
@article{GodefroidBergerVerhaegen1977,
  author = {Godefroid, M. and Berger, J.J. and Verhaegen, G.},
  title = {Multiconfigurational transition state calculations of atomic oscillator strengths. The resonance transition of beryllium},
  journal = {International Journal of Quantum Chemistry},
  year = {1977},
  volume = {12},
  pages = {119-123},
  doi = {10.1002/qua.560120817}
}
Abstract: Atomic oscillator strengths (length and velocity forms) are calculated for a series of transitions using transition Hamiltonians within the Hartree-Fock (HF) approximation. Two methods are implemented: the first defines a transition configuration (TC) corresponding to an average over the occupation numbers of initial and final configurations of the transition considered; the second defines a transition state (TS) corresponding to an average over the energies of the states involved in the transition. In general the TS results agree well with the corresponding HF values, while the TC results show larger discrepancies due to nonphysical self-interactions described in the text. An original method is described for obtaining a multiconfigurational transition state wavefunction. This method (MCTS) is applied to the evaluation of the oscillator strength of the transition Be(1s22s2 1S to 1s 22s2p1P degrees ).
BibTeX:
@article{GodefroidBergerVerhaegen1976,
  author = {Godefroid, M. and Berger, J.J. and Verhaegen, G.},
  title = {A priori calculation of atomic oscillator strengths using correlated transition states},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1976},
  volume = {9},
  article number = {007},
  pages = {2181-2193},
  doi = {10.1088/0022-3700/9/13/007}
}
Abstract: The present paper reports the ab initio evaluation of the electron affinity of oxygen, and the value of its isotope shift. The theoretical results are in good agreement with the recent electron affinity measurements for [Formula Presented] [Formula Presented] by photodetachment microscopy, revealing an “anomalous” isotope shift. The theoretical fine structure of the negative ion [Formula Presented] is also in very good agreement with observation. © 1999 The American Physical Society.
BibTeX:
@article{GodefroidFischer1999,
  author = {Godefroid, M.R. and Fischer, C.F.},
  title = {Isotope shift in the oxygen electron affinity},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {1999},
  volume = {60},
  pages = {R2637-R2640},
  doi = {10.1103/PhysRevA.60.R2637}
}
Abstract: The multiconfiguration Hartree-Fock method extended to include relativistic effects in the Breit-Pauli approximation (MCHF-BP) is tested in the study of the ground configuration of nitrogen-like ions. Fine-structure splittings, E2 and M1 transition rates calculated with the classical (nonrelativistic) form of the magnetic transition operator are presented and compared with other theoretical and experimental results up to Zn XXIV. The astrophysical problem of the high-density limit of the intensity ratio I(2D5/2 to 4S3/2)/I(2D3/2 to 4S 3/2) is discussed on the basis of these new theoretical data.
BibTeX:
@article{GodefroidFischer1984,
  author = {Godefroid, M. and Fischer, C.F.},
  title = {MCHF-BP fine-structure splittings and transition rates for the ground configuration in the nitrogen sequence},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1984},
  volume = {17},
  article number = {008},
  pages = {681-692},
  doi = {10.1088/0022-3700/17/5/008}
}
Abstract: The progress achieved over the last few years in variational Multiconfiguration Hartree-Fock and Configuration Interaction calculations is reviewed. The high level of accuracy which can be reached in the ab initio calculation of atomic properties of light systems is illustrated through the results of calculations of isotope shifts, hyperfine structures and transition probabilities. The active space method and associated restricted active space methods allowing systematic calculations from which the accuracy of the studied property can be estimated will be discussed. We exemplify quality checks through results in small systems for which spectroscopic accuracy is often required. For transition probabilities, recent progress derived from new algorithm developments allowing independent optimization of the states is emphasized.
BibTeX:
@conference{GodefroidFischerJoensson1996,
  author = {Godefroid, M.R. and Fischer, C.F. and Jönsson, P.},
  title = {Multiconfiguration Hartree-Fock calculations of atomic properties in light atoms},
  journal = {Physica Scripta T},
  year = {1996},
  volume = {65},
  pages = {70-83}
}
Abstract: The oscillator strengths of the Mg+ weak transitions 3s 2S1/2-4p 2P3/2, 1/2o at λ = 1239, 1240 angstrom are evaluated using the multiconfiguration Hartree-Fock approach combined with the orbital active set method and configuration-interaction calculations, taking the effect of triple and quadruple excitations into account. The effects of core and core-valence correlation using different optimization schemes are discussed in detail. Relativistic corrections are calculated within the Breit-Pauli approximation.
BibTeX:
@article{GodefroidFroeseFischer1999,
  author = {Godefroid, M. and Froese Fischer, C.},
  title = {Mg+ 3s 2S1/2-4p 2P3/2, 1/2o weak transition probabilities revisited},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1999},
  volume = {32},
  pages = {4467-4483},
  doi = {10.1088/0953-4075/32/18/307}
}
Abstract: Accurate multiconfiguration Hartree-Fock calculations were performed to investigate the J-dependence of the lifetimes of 3s4p3P°J (J = 2, 1, 0) in S V and Cl VI. The relativistic corrections have been included through the Breit-Pauli approximation. The variation with J, observed in S V but not in Cl VI [4], is explained by the selective opening of decay channels resulting from the triplet-singlet mixing and by the J-dependence found in the El spin-allowed transition decay rates where the coulomb and relativistic configuration interaction between 3s4p and 3p3d play a crucial role. The effects of the relativistic shift corrections on the wavefunction compositions and transition probabilities are discussed. New gf-values are reported for the singlet-singlet electric dipole transistions from 3s4p1P°1, taking into account the1P-character loss due to the inter-symmetry mixing. © 1985 IOP Publishing Ltd.
BibTeX:
@article{GodefroidFroeseFischer1985,
  author = {Godefroid, M. and Froese Fischer, C.},
  title = {Relativistic and correlation effects on the lifetimes of 3s4p3p°j levels in mg-like sulphur and chlorine},
  journal = {Physica Scripta},
  year = {1985},
  volume = {31},
  pages = {237-245},
  doi = {10.1088/0031-8949/31/4/004}
}
Abstract: The multiconfiguration Hartree-Fock method is used to calculate wavefunctions in the infinite nuclear mass limit for the terms 2s 2S, 2p 2P o, 3s 2S, 3p 2P o, 3d 2D and 4s 2S of lithium-like ions (3 ≤ Z ≤ 8). Transition data, isotope shift parameters and hyperfine structure electronic contributions involving the six terms of the six ions are evaluated ab initio and compared with the most recent observations and other theoretical calculations when available. The isotopes 7,6Li I, 11,10,9,7Be II, 14,13,12C IV, 15,14N V and 18,17,16 O VI are considered in the analysis of the mass isotope shifts.
BibTeX:
@article{GodefroidFroeseFischerJoensson2001,
  author = {Godefroid, M. and Froese Fischer, C. and Jönsson, P.},
  title = {Non-relativistic variational calculations of atomic properties in Li-like ions: Li I to O VI},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {2001},
  volume = {34},
  pages = {1079-1104},
  doi = {10.1088/0953-4075/34/6/308}
}
Abstract: Transition probabilities of the radiative decay processes of the excited levels 2p4(3P)3d 4D7/2, 2F7/2 and 4F7/2 of the fluorine-like neon ion (Ne+) are evaluated by variational calculations using superposition of configurations in the Breit-Pauli approximation. The strong 2F7/2-4F7/2 relativistic mixing is discussed in terms of level designation and doublet-quartet intensity transfer. A detailed comparison of the results with other theories and with the NIST measurements of branching fractions, combined with lifetime measurements, confirms problems on the experimental side.
BibTeX:
@article{GodefroidHibbert2000,
  author = {Godefroid, M.R. and Hibbert, A.},
  title = {Theoretical lifetimes and branching fractions of 2p4(3P)3d 4D7/2, 2F7/2 and 4F7/2 in Ne II},
  journal = {Molecular Physics},
  year = {2000},
  volume = {98},
  pages = {1099-1106},
  doi = {10.1080/00268970050080465}
}
Abstract: Recent ab initio variational calculations of radiative transition probabilities, isotope shifts and hyperfine structures are described in the spirit of the EGAS tradition for plenary talks. A few simple cases are selected to make the exposé at a level accessible to non-specialists in the field and to illustrate how computational atomic structure can be used in atomic spectroscopy for testing theoretical models or experimental results, predicting properties or interpreting them in terms of electron correlation. The effects inherent in the multiconfiguration Hartree-Fock method due to its variational nature are emphasized through some simple analysis of the wave function spatial distribution in correlation with the model used. © Physica Scripta 1998.
BibTeX:
@conference{GodefroidJoenssonFischer1998,
  author = {Godefroid, M.R. and Jönsson, P. and Fischer, C.F.},
  title = {Atomic structure variational calculations in spectroscopy},
  journal = {Physica Scripta T},
  year = {1998},
  volume = {78},
  pages = {33-46}
}
Abstract: The atomic d shell is explored from the perspective of the quark model of the atom. In this scheme, all the states are generated by four statistically independent fictitious particles (the quarks), each with angular momentum 3/2, augmented by two parity labels. The detailed quark expansions are given for the two 2D terms of d3, and the results are compared to the classic analysis of Condon and Shortley (1935). Matrix elements of single-electron tensor operators and of the Coulomb interaction are calculated in the quark scheme, and the connection to the conventional approach is made. The diagonal sum method of Slater is applied to the quark states and extensions to many-electron operators are discussed. The correspondence between the quark model and the traditional method implies relations between various n-j symbols, and this is illustrated by two special cases. © 1994 IOP Publishing Ltd.
BibTeX:
@article{GodefroidJuddVaeck1994,
  author = {Godefroid, M.R. and Judd, B.R. and Vaeck, N.},
  title = {Applying the quark model to the atomic d shell},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1994},
  volume = {27},
  pages = {3635-3652},
  doi = {10.1088/0953-4075/27/16/011}
}
Abstract: A new method to discretise the Schrodinger equations has been described recently and applied successfully to simple quantum mechanical and nuclear Hartree-Fock problems. The method is based on an accurate approximation of a variational calculation. The authors apply this approach in atomic structure calculations by discretising on Laguerre meshes the Schrodinger equation for hydrogen and the Hartree-Fock and configuration interaction equations of two-electron systems. They investigate the accuracy of the method for the ground states and some of the excited states of H, He and H-. They illustrate the striking simplicity of the Hamiltonian matrix elements arising from the Lagrange functions properties when using the Gauss quadrature integration formula and test its accuracy as a function of the number of points defining the mesh. They also test the quality of the Lagrange function basis set by checking sum rules and by calculating the second-order energy of helium.
BibTeX:
@article{GodefroidLievinHeenen1989,
  author = {Godefroid, M. and Lievin, J. and Heenen, P.-H.},
  title = {Laguerre meshes in atomic structure calculations},
  journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
  year = {1989},
  volume = {22},
  article number = {006},
  pages = {3119-3136},
  doi = {10.1088/0953-4075/22/20/006}
}
Abstract: The singly excited functions satisfying Brillouin theorem are expressed as linear combinations of configuration‐state functions for any spin and spatial symmetries (atomic or molecular) and for any reference wave function. The generality of the formulation is ensured by the use of the irreducible tensor method that can be adapted to any symmetry point group of interest. The expansion coefficients are simply written as products of fractional parentage coefficients, spin‐ and orbit‐recoupling coefficients, and phase factors. The formalism is illustrated for some atomic (Kh) and molecular (C∞v, C3v, and Td) configurations. Group theoretical techniques are also used to correlate the Brillouin conditions within a chain of groups. Copyright © 1991 John Wiley &amp; Sons, Inc.
BibTeX:
@article{GodefroidLievinMetz1991,
  author = {Godefroid, M. and Lievin, J. and Metz, J.‐Y.},
  title = {Symmetry adapted formulation of the generalized Brillouin theorem},
  journal = {International Journal of Quantum Chemistry},
  year = {1991},
  volume = {40},
  pages = {243-264},
  doi = {10.1002/qua.560400207}
}
Abstract: General mathematical expressions are derived for the weighting coefficients of the configuration state functions defining the singly excited function satisfying Brillouin's theorem for complex atomic configurations. The relations are illustrated for different cases and tested numerically by the cancellation of the Brillouin matrix elements using the Hartree-Fock solution for the reference function.
BibTeX:
@article{GodefroidLievinMetz1987,
  author = {Godefroid, M. and Lievin, J. and Metz, J.Y.},
  title = {Brillouin's theorem for complex atomic configurations},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1987},
  volume = {20},
  article number = {004},
  pages = {3283-3296},
  doi = {10.1088/0022-3700/20/14/004}
}
Abstract: The Racah fractional parentage coefficients (1943) used in atomic structure calculations contribute to a part of an ordinary unitary matrix transformation. In the present paper the authors describe three different approaches for completing this matrix using (i) projection operator techniques, (ii) the factorisation lemma of Racah and (iii) the spin-free formalism already used in theoretical studies of nuclear structures. The authors hope to give a deeper insight into the fractional parentage expansion and to its inverse transformation. © 1987, IOP Publishing Ltd.
BibTeX:
@article{GodefroidLievinMetz1987a,
  author = {Godefroid, M. and Lievin, J. and Metz, J.Y.},
  title = {Inversion of the fractional parentage matrix},
  journal = {Journal of Physics A: Mathematical and General},
  year = {1987},
  volume = {20},
  pages = {1645-1653},
  doi = {10.1088/0305-4470/20/7/011}
}
Abstract: Quantitative comparisons between observed and theoretical wavelengths and intensity ratios are made to confirm the identification of some emission lines observed in the spectra of Na- and Mg-like ions as electric quadrupole (E2) transitions. The transition rates of these lines connecting D symmetry levels and the ground level are calculated using the multiconfiguration Hartree-Fock (MCHF) wavefunctions. © 1985 IOP Publishing Ltd.
BibTeX:
@article{GodefroidMagnussonZetterbergEtAl1985,
  author = {Godefroid, M. and Magnusson, C.E. and Zetterberg, P.O. and Joelsson, I.},
  title = {Forbidden transitions in na− and mg-like spectra},
  journal = {Physica Scripta},
  year = {1985},
  volume = {32},
  pages = {125-128},
  doi = {10.1088/0031-8949/32/2/006}
}
Abstract: A new method to deal with nonorthogonalities in transition calculations has been implemented and tested. Large-scale transition calculations using the multiconfiguration Hartree-Fock (MCHF) method have been performed for the resonance line of B II at 1362 Å. In these calculations the orbital sets of the initial and final-state wavefunctions have not been assumed to be equal but have been optimized independently. The calculated weighted multiplet oscillator strength gf = 0.999 has an estimated uncertainty of less than 0.5%. Together with the previously calculated isotope shift and hyperfine structure (Jönsson, Johansson, & Froese Fischer 1994), all the important atomic parameters needed for a detailed modeling of the B II resonance line in high-resolution astrophysical spectra are now available with high accuracy.
BibTeX:
@article{GodefroidOlsenJoenssonEtAl1995,
  author = {Godefroid, M. and Olsen, J. and Jönsson, P. and Fischer, C.F.},
  title = {Accurate multiconfiguration Hartree-Fock calculations of oscillator strengths in light atoms: The boron (B II) line at 1362 Å},
  journal = {Astrophysical Journal},
  year = {1995},
  volume = {450},
  pages = {473-476},
  doi = {10.1086/176157}
}
Abstract: The hyperfine structure constants for the 1s22s22p3 -4S ground state in nitrogen and the 1s22s22p33s 5So excited state in oxygen are calculated using the MCHF Atomic Structure Package. The single excitation picture is explored through the use of compact wave functions allowing radial non-orthogonalities. Electron correlation is described through numerical multiconfiguration Hartree-Fock calculations for configuration expansions obtained by allowing all single and double excitations from the reference configuration to an active set of orbitals. The latter is increased in a systematic way allowing the convergence of the hyperfine parameters to be studied. Three- and four-particle effects are shown to be important and are taken into account in a sequence of large configuration interaction calculations. The final results are in good agreement with experiment. © Springer-Verlag 1997.
BibTeX:
@article{GodefroidVanMeulebekeJoenssonEtAl1997,
  author = {Godefroid, M.R. and Van Meulebeke, G. and Jönsson, P. and Froese Fischer, C.},
  title = {Large-scale MCHF calculations of hyperfine structures in nitrogen and oxygen},
  journal = {Zeitschrift fur Physik D-Atoms Molecules and Clusters},
  year = {1997},
  volume = {42},
  pages = {193-201},
  doi = {10.1007/s004600050354}
}
Abstract: Accurate wavefunctions obtained by the MCHF method in its reduced form were used to compute the oscillator strengths for all possible electric dipole (E1) and electric quadrupole (E2) transitions between the states 11S, 21,3(S,P0), 31,3D and 41,3F 0 of helium-like systems ranging from He I to Ne IX. The length and velocity forms of the oscillator strengths are in close agreement in all cases; the correlation contributions to the gf values are discussed. The present results are the most accurate to date for E11,3(3D-4F0) and for all the E2 transitions.
BibTeX:
@article{GodefroidVerhaegen1980,
  author = {Godefroid, M. and Verhaegen, G.},
  title = {MCHF calculations of electric dipole and quadrupole oscillator strengths along the helium isoelectronic sequence},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  year = {1980},
  volume = {13},
  article number = {007},
  pages = {3081-3098},
  doi = {10.1088/0022-3700/13/16/007}
}
Abstract: The equilibrium vapor effusing from a Knudsen cell, in which solid ND 4Cl was evaporated, was analyzed by a quadrupole mass spectrometer. In the temperature range considered (335°-485°K) the main vaporization process corresponds to the decomposition of the solid towards gaseous ND 3 and DCl; the measured enthalpy change ΔH°407 dec[ND4Cl(s)]=42.6±2.0 kcal mole-1 is very close to that measured for NE4Cl: ΔH°407 dec[NH4Cl(s)]=42.5 kcal mole-1. Apart from the main gaseous species, small proportions (5×10-5-2×10 -3) of ND4Cl molecules were also observed. The ND 4Cl molecule fragments (&gt;99%) under electron impact and yields the ND4+(m/e=22) ion. From the observed ion intensity ratios, as well as their dependence on temperature, D0°(NH 4Cl⇌NH3+HCl)= 10.0±3.0 kcal mole -1 was obtained confirming Clementi's computed prediction &lt;14.0 kcal mole-1.
BibTeX:
@article{GoldfingerVerhaegen1969,
  author = {Goldfinger, P. and Verhaegen, G.},
  title = {Stability of the gaseous ammonium chloride molecule},
  journal = {The Journal of Chemical Physics},
  year = {1969},
  volume = {50},
  pages = {1467-1471},
  doi = {10.1063/1.1671212}
}
Abstract: We have used continuous-wave cavity ring-down and femto-Fourier transform-cavity-enhanced absorption spectrometers to record the spectrum of the OH-stretching + CH-stretching (ν1 + ν2) combination band in trans-formic acid, with origin close to 6507 cm-1. They, respectively, allowed resolving and simplifying the rotational structure of the band near its origin under jet-cooled conditions (Trot = 10 K) and highlighting the overview of the band under room temperature conditions. The stronger B-type and weaker A-type subbands close to the band origin could be assigned, as well as the main B-type Q branches. The high-resolution analysis was hindered by numerous, severe perturbations. Rotational constants are reported with, however, limited physical meaning. The ν1 + ν2 transition moment is estimated from relative intensities to be 24°away from the principal b-axis of inertia. © 2015 AIP Publishing LLC.
BibTeX:
@article{GolebiowskiFoeldesVanfleterenEtAl2015,
  author = {Golebiowski, D. and Földes, T. and Vanfleteren, T. and Herman, M. and Perrin, A.},
  title = {Complementary cavity-enhanced spectrometers to investigate the OH + CH combination band in trans -formic acid},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  article number = {014201},
  doi = {10.1063/1.4923256}
}
Abstract: We have recorded Fourier transform spectra of OCS between 6170 and 6680cm-1, and between 7700 and 8160cm-1 using a femto/OPO laser absorption source and cavity enhanced spectroscopy. Equivalent absorption path lengths varying between 7 and 13km were obtained depending on the specific spectral region. In the lower and higher energy ranges, 7 and 12 new bands were observed, respectively, while improved results were gained on those previously reported in the literature. Some of these data brought significant, new information on the rovibrational energy pattern in OCS that triggered an update of the latest published global polyad model (Rbaihi et al. J Mol Spectrosc 1998;191:32 [15]). The new fit includes for the first time all overtone data since published in the literature, covering the range 6200-13950cm-1, as well as all known lower energy ones. All data selected for the global analysis of carbonyl sulphide 16O12C32S are provided as supplementary information. The previous polyad model was extended to include the inter-polyad anharmonic k1113 and Coriolis C11222 interactions, leading to simultaneously deal with sets of nine interacting polyad matrices at a time, each polyad defined by N=2v1+v2+4v3 (with 1-3 the conventional normal modes in OCS). We have obtained a statistical agreement with all experimental data with an estimated standard deviation better than unity (σ=0.7568). The fit produced 141 molecular parameters, of which 4 concern the new inter-polyad resonances. They have been used to calculate effective rovibrational parameters for all sub-states up to more than 12,000cm-1, listed in a Depository (Appendix B). A list of line parameters, covering the measured spectral ranges and including line intensities determined using previously recorded Fourier transform spectra of the two strongest bands observed in the present work, was generated in HITRAN format. It is also provided as supplementary information. © 2014 Elsevier Ltd.
BibTeX:
@article{GolebiowskiGhellinckdElseghemVaernewijckHermanEtAl2014,
  author = {Golebiowski, D. and de Ghellinck d'Elseghem Vaernewijck, X. and Herman, M. and Auwera, J.V. and Fayt, A.},
  title = {High sensitivity (femto-FT-CEAS) spectra of carbonyl sulphide between 6200 and 8200cm-1, and new energy pattern in the global rovibrational analysis of 16O12C32S},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {149},
  pages = {184-203},
  doi = {10.1016/j.jqsrt.2014.07.005}
}