Theoretical studies on SO x ( x = 1–3) formation in the reaction of CH 3SO radical with O 3

Abstract

The reaction of CH 3SO radical with O 3 has been studied at MP2/6-311++G (2df, p) level. Geometries of the reactants, transition states (TS) and products have been optimized and the transition states are found for the first time. The breakage and formation of the chemical bonds in the reaction have been discussed by the topological analysis of electronic density. The following conclusions were obtained: Because the reaction has relative high energy barrier, the CH 3SO can be oxidized by O 3 at high temperature. The major oxidized products, SO 2 and SO 3, are the precursor substance of acid rain. Furthermore, OSOO → SO 3 ( D 3h) reaction consists of two elementary reaction, the topological analysis of electron density results show that the ring transitional structure region exists not only in OSOO → SO 3 ( C s) process but also in SO 3 ( C s) → SO 3 ( D 3h) process. It is the first time we found a ring transitional structure exists in two elementary reactions. And there are two kinds of S–O bond characters in different SO 3 isomers.