UFR de Physique

Propositions de stages en laboratoire -- M2

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High-resolution rotational spectroscopy of catechol : a precursor of biomass burning organic aerosols

  • 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): Frank Hindle, Gaël Mouret, Robin Bocquet, Guillaume Dhont
  • Mots clés: catechol, aerosol precursor, rotational spectroscopy, submillimeter instrumentation
  • Fiche complète en PDF : Fiche complète en PDF

Atmospheric aerosol particles strongly influence the global atmosphere, and their contribution to climate change is versatile. Especially Secondary Organic Aerosols (SOA) play a major role in the impact of atmospheric chemistry on climate. While the formation of SOA from different terpenes has been studied in detail, there is still a lack of knowledge of SOA formation from Aromatic Precursors (AP). An appropriate AP for SOA formation is catechol, which is also reported as a strong emission from combustion leading to so-called biomass-burning organic aerosols (BBOA). Aerosol formation from catechol has been studied in LPCA, obtaining large mass yields in a smog-chamber in the presence of ozone. Recently, two LPCA research groups with expertise in THz spectroscopy and chemical reactivity were combined to study AP, which form a significant component of biomass combustion emissions: a database of vibrational cross-sections has been built - reactivity studies of AP with main atmospheric oxydants have demonstrated the potential of AP to form SOA. Intermediate compounds in the SOA formation have been identified and the hygroscopic properties have been studied. Today, we aim to perform high resolution rovibrational studies of AP and the catechol molecule has been targeted. The main goal of this study is the demonstration of the capability to monitor catechol at room temperature in gas phase using submillimeter rotational spectroscopy. For this research training, we propose to measure for the first time the submillimeter rotational spectrum of catechol using 2 spectrometers: a versatile spectrometer based on a frequency multiplication chain and the new chirped pulse submillimeter instrument. In addition to the experimental part, a large part of the research training will be dedicated to spectroscopic analyses using a large variety of programmes (genetic algorithms, LWWa, SPFIT/SPCAT programs…). Some financial support will be provided and a continuation in PhD thesis is possible.