Ab initio study on the reaction mechanism of ozone with bromine atom

摘要

Ab initio calculations of the potential energy surface (PES) for the Br+O-3 reaction have been performed using the MP2, CCSD(T), and QCISD(T) methods with 6-31G(d), 6-311G(d), and 6-311+G(3df). The reaction begins with a transition state (TS) when the Br atom attacks a terminal oxygen of ozone, producing an intermediate, the bromine trioxide (M), which immediately dissociates to BrO+O-2. The geometry optimizations of the reactants, products, and intermediate and transition states are carried out at the MP2/6-31G(d) level. The reaction potential barrier is 3.09 kcal/mo at the CCSD(T)/6-311+G(3df)//MP2 level, which shows that the bromine atom trends intensively to react with the ozone. The comparison of the Br+O-3 reaction with the F+O-3 and Cl+O-3 reactions indicates that the reactions of ozone with the halogen atoms have the similar reaction mechanism. (c) 2006 Wiley Periodicals, Inc.