Vibrational relaxation in atom exchange reactions: A classical trajectory study of H + H2(ν) and D + D2(ν) collisions using an accurate potential

A quasiclassical trajectory study has been carried out to investigate the dynamics of collisions between H + H₂(1 ? ν ? 4) and D + D₂(1 ? ν ? 4), using the accurate Yates-Lester potential. Reaction is selectively enhanced by the vibrational excitation of the diatomic reagent, as judged by information theory, but the degree of selectivity falls as the vibrational energy is successively increased. The calculated results are in fair agreement with experimental measurements on the removal of H₂(ν = 1) by H but not with those for D₂(ν = 1) by D.