Theoretical study of the adsorption of Methyl Iodide on model sea-salt surfaces

Oceans, through algae and phytoplankton activities, are the main source of iodine, including monohalogenated organic compounds as CH3I [1].  There is missing knowledge about interactions between iodinated compounds and aerosols in the troposphere. In this context, this work investigates the adsorption of gaseous iodomethane (CH3I) on model sea-salt aerosols at various humidities. The water coverage tends to stabilize CH3I at the salt surface. The lifetime of CH3I in the atmosphere (in gas phase or adsorbed on aerosols) may be altered by its reaction with gas phase radicals. The reaction of CH3I with OH is thus investigated both in gas phase and in presence of water by means of quantum mechanical calculations. References:[1] Saiz-Lopez et al, Chem. Rev. 2012, 112, 1773–1804. Acknowledgments: I-SITE ULNE OVERSEE project (contract ANR-16-IDEX-004)The CaPPA project (Chemical and Physical Properties of the Atmosphere) is funded by the French National Research Agency (ANR) through the PIA (Programme d’Investissement d’Avenir) under contract « ANR-11-LABX-0005-01 » and by the Regional Council « Hauts-de-France » and the « European Funds for Regional Economic Development » (FEDER)