UFR de Physique

Propositions de stages en laboratoire -- M2

Les offres sont actualisées en mai. Par exemple, les offres de stages pour l'année universitaire 2015-2016 seront mises en place en mai 2015, les offres de stages pour l'année universitaire 2016-2017 seront mises en place pour en mai 2016, etc.

Terahertz (THz) photomixing high resolution spectroscopy of GeH4: a desequilibrium species for giant planet atmospheres

  • Option Lumière-Matière, Générique du parcours Lumière-Matière
  • Laboratoire: Laboratoire de Physico-Chimie de l'Atmosphère (LPCA)
  • Responsable du stage: CUISSET Arnaud (arnaud.cuisset@univ-littoral.fr, .13)
  • Co-responsable(s): Vincent Boudon (université de Bourgogne), Gaël Mouret, Francis Hindle, Robin Bocquet
  • Mots clés: germane, THz photomixing, spherical top, planetary atmospheres, high-resolution spectrocopy
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The interest in high resolution study of germane infrared spectra is motivated by several reasons. Firstly, high resolution spectra of germane can be interesting for studying the atmospheres of giant gas-planets, such as Jupiter and Saturn, and its presence should be taken into account when studying their atmospheric composition and chemistry. Germane in a natural isotopic composition is used for producing high-purity germanium in semiconductor industry. From a spectroscopical point of of view, GeH4 is a spherical top species with no permanent dipole moment. Therfore its detection in atmospheres has been done from IR rovibrational transitions. Nevertheless, we demonstrated by methane studies the possibility to observe in the THz frequency range pure rotational transitions induced by centrifugal distortion. In the case of GeH4, those transitions have never been observed. In this research training, we want to use the THz photomixing LPCA set-up to measure for the first time the pure rotational THz spectrum of GeH4. This laboratory study will open a new spectral window for the astrophysical detection of GeH4 in giant planet atmospheres using satellite THz on-board instrumentations. The proposed subject requires experimental skills in spectroscopy, optics and electronics. The candidate will have the opportunity to use a unique set-up in the international community. The results will be analyzed in collaboration with the Dijon group and could lead to a publication in an astrophysical journal. The training will be performed in the THz group of the LPCA at Dunkerque. Some financial support will be provided and a continuation in PhD thesis is possible.