Quasi-classical Trajectory Study of the Intramolecular Isotope Effect in the Reaction O(³P)+H₂/HD

Theoretical studies of the dynamics of the reactions O(³P)+H₂/HD(v=0, j=0)→OH+H have been performed with quasi-classical trajectory method (QCT) on an ab initio potential surface for the lowest triplet electronic state of H₂O(³A" ). The QCT-calculated integral cross sections are in good agreement with the earlier time-dependent quantum mechanics results. The state-resolved rotational distributions reveal that the product OH rotational distributions for O+HD have a preference for populating highly internally excited states compared with the O+H₂ reaction. Distributions of differential cross sections show that directions of scattering are strongly dependent on the choice of quantum state. The polar-ization dependent generalized differential cross-sections and the distributions were calculated and a pronounced isotopic effect is revealed. The calculated results indicate that the product polarization is very sensitive to the mass factor.