A THEORETICAL-STUDY OF THE H+SO2 REACTION

Ab initio UHF and MP2 calculations have been used to characterize the relative stabilities, equilibrium geometries, and harmonic frequencies of the intermediates involved in the H + SO2 reaction. Calculations f or the entrance channel potentials at the MP2/DZP level of theory indi cate pure repulsion for planar attack (2A' surface) by the H atom on t he S atom of SO2 and an 11 kcal/mol barrier to the nonplanar (2A'' sur face) attack. Much larger barriers are predicted for the formation of the HOSO adducts on this surface. Implications to experiments involvin g the reaction of SO2 with translationally hot H atoms are discussed.