Theoretical study of the role of adducts in the atmospheric oxidation of dimethyl sulfoxide by OH, O2 and O3 and the kinetics of the reaction DMSOÂ +Â OH

Using ab initio calculations, we have identified the stable weakly bound complexes between DMSO and the atmospheric oxidants OH, O2 and O3. Complexes with O2 and O3 are very weakly bound, and it will not be significant in the atmospheric chemistry of DMSO. We have found three very stable complexes with OH and their influence on the mechanism of the reaction DMSO + OH was investigated. The formation of an adduct bound through the sulfur atom of DMSO influences the course of the reaction, making it slower. At 298 K and 1 atm of pressure, the unique products will be CH3S(O)OH and CH3, and the overall rate constant was calculated as being 1.44 × 10−10 cm3 molecule−1 s−1, in excellent agreement with experimental data.