Quasi-Classical Trajectory Dynamics Study on the Reaction of H with HO2

Quasi-classical trajectory (QCT) simulations, based on our previously reported PES data (Bull. Chem. Soc. Jpn. 2007, 80, 1901) were carried out to study the dynamics of the lowest singlet potential energy surface of H + H0 2 reaction. The surface consists of two potential wells due to formation of water oxide (H 2 00 * ) and hydrogen peroxide (HOOH * ). A detailed consideration of the dynamics of the intermediates H 2 00 * and HOOH * reveals that water oxide and hydrogen peroxide geometries, largely undergo asymmetric or symmetric stretching like motions until they dissociate. The QCT calculations revealed that the reaction is very sensitive to the vibrational excitation of HO 2 . In general, QCT integral, reactive reaction cross-sections and rate constants are found to be in good agreement with their QM and experimental counterparts, indicating that, for this system, the motion of the nuclei during reactive encounters is largely classical and that quantum effects, such as tunneling, play a relatively minor role in the overall dynamics. The intramolecular vibrational energy redistribution (IVR) involving excitation of the OH and 00 bonds in HOOH is investigated. The calculated IVR time constants describing energy flow out of the OH and 00 stretching modes are reported. It is found that calculated IVR time constants decrease exponentially with increasing the amount of energy put in the relevant modes.