Classical trajectory study of the effect of vibrational energy on the reaction of molecular hydrogen with atomic oxygen

Abstract

The dynamics of the reaction O+H2(v) →OH+H is studied by means of three dimensional classical trajectory calculations on an LEPS potential energy surface.Rate constants are calculated for the two cases in which the H2 molecule is initially in the v=0 and v=1 vibrational state. In the temperature range 298–1000 °K these rates are fit very well by the formulas (cm3 molecule−1 sec−1) k=2.81T×10−14 exp(−4279/T) and k=4.65T×10−14 exp(−1868/T). The calculated value of k at 300 °K is 2.8×10−14 cm3 molecule−1 sec−1 which is below the upper bound established by Birely [J. H. Birely, J.V.V. Kasper, F. Hai, and L. A. Darnton, Chem. Phys. Lett. 31, 220 (1975)]. The branching ratio Γ, defined as the ratio of the rates for populating the v′=1 and v′=0 state of OH when H2 is initially in the v=1 state is also calculated and fit by the expression Γ=2.3 exp(196/T). The value at 300 °K is 4.4.