COMP 14 |
Theoretical study of atmospherically important complexes of Criegee intermediate with water clusters and its reactions
| Andrew Ryzhkov and Parisa Ariya. Department of Atmospheric and Oceanic Sciences, and Chemistry, McGill University, 805 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada |
| Gas-phase reactions with ozone are significant removal process for volatile unsaturated hydrocarbons in troposphere, which also produce atmospherically important species: HO, HO2, organic and inorganic peroxides. The primary product of the ozonolysis of alkenes is the Criegee intermediate (CI), the most important reaction of which is interaction with water. In present work ab initio and density functional methods were applied to evaluate importance of formation of CI complexes with water clusters for atmospheric reactions. Various structures CI…(H2O)n with n=1..4 were calculated and minimal configurations are found. In addition, the reactions of these complexes were investigated; energy barriers and rate constants were estimated. The rate constant of overall process was calculated, and its dependence on temperature and relative humidity was determined. Reaction rates for all pathways were estimated based on found rate constants and typical concentrations of the reactants in atmosphere. The further reactions of products and its impact on the chemistry of atmosphere are discussed. 
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