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.

Measurements of SOA precursors in an atmospheric simulation chamber using rotational spectroscopy

  • Option International « Atmospheric Environnement » du parcours Lumière-Matière
  • Laboratoire: Laboratoire de Physico-Chimie de l'Atmosphère (LPCA)
  • Responsable du stage: CUISSET Arnaud (arnaud.cuisset@univ-littoral.fr,
  • Co-responsable(s): CŒUR Cécile
  • Mots clés: aerosol precursor, Atmospheric Simulation Chamber, multipass cell, rotational spectroscopy, submillimeter instrumentation
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Volatile organic compounds (VOCs) are emitted into the atmosphere by natural processes (vegetation, oceans ...) or resulting from human activities (transport, industry ...). In order to study their atmospheric fate, researchs on their reactivity with the main atmospheric oxidants are carried out in atmospheric simulation chambers (ACS). A new ACS, CHARME for CHamber for the Atmospheric Reactivity and the Metrology of the Environment, was recently developed. The experiments conducted in CHARME are part of the Labex Cappa dedicated to the study of gaseous biogenic precursors at the origin of Secondary Organic Aerosols (SOA) formation in the troposphere. The originality of CHARME compared to the ACS present in the national and international communities of atmospheric physico-chemists is its coupling with innovative optical methods (IBBCEAS, FRS, QCL, FTIR, THz,...) for the in situ monitoring of stable and unstable molecules involved in atmospheric reactivity. The success of these methods lies in the ability to achieve sufficient sensitivity to detect and quantify the targeted species in the ACS. To achieve this goal, it is necessary to have within the chamber a multiple reflection system to maximize the light / matter interaction distance. Recently, we have obtained funding to develop, within CHARME, a multi-pass cell arranged in a CHERNIN configuration allowing to reach long optical path even at long wavelengths. We propose as part of this M2 training to participate in a world first by performing measurements of submillimeter rotational spectroscopy of VOC biogenic precursors of SOA directly in CHARME and benefiting from a length of interaction light / matter of several hundred meters. The targeted compounds will be oxygenated aromatic semi-volatile compounds whose spectroscopy and reactivity have been studied in recent years in our laboratory. The proposed work is mainly experimental in order to develop its skills in optics, molecular spectroscopy and atmospheric physico-chemistry. Some financial support will be provided and a continuation in PhD thesis is possible.