UFR de Physique

Propositions de stages en laboratoire -- M2

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Theoretical study of sulfur dioxide reactivity on organic aerosol surfaces

  • Option International « Atmospheric Environnement » du parcours Lumière-Matière
  • Laboratoire: Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM)
  • Responsable du stage: DUFLOT Denis (denis.duflot@univ-lille1.fr, 03.20.43.49.80)
  • Co-responsable(s): Céline Toubin
  • Mots clés: electronic structure, molecular dynamics, aerosols, reactivity
  • Fiche complète en PDF : Fiche complète en PDF

Sulfur dioxide is a trace gas in the Earth atmosphere, with typical concentrations of 15 ppbv in the most polluted areas. It nevertheless plays an important role in atmospheric chemistry and physics. For example, through the formation of sulfuric acid H2SO4, it can trigger the formation of new particles. According to the last IPCC report, these particles could have a cooling effect on the global temperature. Another important aspect concerns the reactivity of SO2 at the surface of aerosol particles, either mineral (dust) or organic (fatty acids). These heterogeneous processes have been studied experimentally at the macroscopic level but a detailed understanding at the molecular level is still missing. A theoretical approach is therefore necessary. The objective of the research training is to use numerical simulations to study the reactivity of SO2 at the surface of organic aerosols consisting in fatty acids (typically oleic and stearic acids). To do this, High Performance Computers (HPC) will be used. Two classes of methods may be employed : Molecular Mechanics (MM) methods, based on Newtonian mechanics, and Quantum Mechanics (QM) approaches. For the particulate phase, the size of the system requires a mixt QM/MM methodology. The role of humidity (presence of water molecules at the aerosol surface) will also be investigated.