EFFECTS OF TRANSLATIONAL, ROTATIONAL, AND VIBRATIONAL-ENERGY ON THE DYNAMICS OF THE D+H2 EXCHANGE-REACTION - A CLASSICAL TRAJECTORY STUDY

Quasiclassical trajectory (QCT) calculations for the D + H-2(upsilon,j) --> HD + H system have been performed on the Liu, Siegbahn, Truhlar, Horowitz (LSTH) potential energy surface in order to study the combined effects of translation, rotation, and vibration on the reactivity. The range of initial conditions covered has been E(T) = 0.25-1 eV, upsilon = 0, 1, and 2 and j = 0-12. Integral cross sections, opacity functions, solid angle differential cross sections, and the energy partitioning among the products' degrees of freedom have been obtained. The minimum in the dependence of the total cross section with rotational excitation observed in previous QCT calculations for upsilon = 0 and upsilon = 1 at low collision energies is here verified also for upsilon = 2. The center-of-mass (c.m.) angular distributions of the scattered HD product are predominantly backward with respect to the direction of the D incoming atom, at low energies, but they broaden markedly and become more forward with increasing total energy. Translational and vibrational excitation in the reactants are largely adiabatic and tend to remain as translation and vibration in the products. Where they can be compared, present results are in good agreement with recent quantum mechanical calculations and with experimental measurements.