Exact quantum mechanical study of kinetic isotope effects in the collinear reaction Cl + H2 → HCl + H. The H2/D2 and the H2/T2 isotope effects

Exact quantum mechanical probabilities for the collinear reaction of chlorine atoms with H2, D2, and T2 in their ground and first vibrational excites states, were calculated for a semiempirical LEPS potential energy surface. These probabilities were used to calculate the kinetic isotope effects kCl+H2/kCl+D2 and kCl+H2/kCl+T2 which are compared with experimental data and with results of transition state theory calculations. The effect of the vibrational excitation of the hydrogen molecules on the rate of their reaction with chlorine atoms was also studied.