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

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(3 df ). 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/mol at the CCSD(T)/6‐311+G(3 df )//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. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007