Quantum scattering calculations of the H+O2→O+OH reaction

We report quantum mechanical calculations of the H + O-2 --> OH + O reaction for total angular momentum quantum number J = 0 in the absence of recombination. Our calculations employ two different potential energy surfaces-the widely used semiempirical double many-body expansion (DMBE IV) potential surface of Pastrana et al. (J. Phys. Chem. 1990, 94, 8073) and an ab initio potential surface by Troe and Ushakov (J. Chem. Phys. 2001, 115, 3621) which is yet to be tested against detailed quantum dynamics calculations. We explore the sensitivity of the dynamics to details of the potential energy surface. The reaction is dominated by narrow resonances due to the formation of the HO2 radical, and results are sensitive to details of the potential energy surfaces. Thermal rate coefficients evaluated using a J-shifting approximation differ by about 50% on the two potential surfaces. Calculations show that, within the J-shifting approximation, the Troe-Ushakov potential surface yields rate coefficients that are in better agreement with experiments.