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Experimental Spectroscopy Atmospheric

Thomas Vanfleteren


  • BA in chemistry, ULB (2008-2011)
  • MA in chemistry, ULB (2011-2013)
  • Master thesis: Etude par spectroscopie à haute résolution de la bande ν13 du complexe de van der Waals ammoniac-argon, Ar−NH3
  • PhD student in Sciences, ULB, FRIA grant (2013-present)

PhD project

Concerted, high-resolution spectroscopic investigation of van der Waals complexes and of collisional line profiles of NH3 and H2O.

The project is centered on the high-resolution spectroscopic study of two processes induced by intermolecular collisions in the gas phase: the formation of van der Waals complexes and the broadening and shifting of spectral lines. This research concern ammonia and water, interacting with collisional partners such as rare gases and H2.

The ammonia- and water-containing van der Waals complexes with various rare gases will be studied by cavity ringdown spectroscopy (CRDS) in the region of the ν13 band of NH3 (1.5 μm) and water (1.4 μm), using the FANTASIO+ setup (Fourier transform, diode laser and quadrupole spectrometers interfaced to a supersonic expansion). We will assign the vibration-rotation structures observed. We will also investigate the profile of lines belonging to the same band to determine properties of the complexes (predissociation lifetimes...) or of the supersonic expansion (rotational temperature...).

Concerning the line parameters, the absorption spectra of the ν2 band (10 μm) or of the 2ν413 vibrational system (3 μm) of NH3, pure and diluted in various rare gases and H2 at total pressures up to ~1 atm, will be recorded using high-resolution Fourier transform spectrometry. The quality of existing line positions and intensities will be evaluated. The broadening and shift parameters will then be measured using multi-spectra analysis. This work will involve a study of the possible impact on the obtained parameters of interferences between lines and of the line profile model used.


See here

Université Libre de Bruxelles – Faculté des Sciences