The dynamics of the O(1D)+HD reaction: A quasiclassical trajectory multisurface study

Abstract

Integral and differential cross sections for the $\mathrm{O}{(}^1\mathrm{D)+}\mathrm{HD}$ reaction have been obtained from adiabatic and nonadiabatic quasiclassical trajectory calculations performed on new ab initio versions of the ${\text{1A}}^{\prime },$ ${\text{1A}}^{″}$ and ${\text{2A}}^{\prime }$ potential energy surfaces at the collision energies of 0.089 and 0.196 eV (2.05 and 4.53 kcal/mol, respectively). Results are reported for both the OH+D and OD+H exit channels of reaction. The new data are compared with those from previous theoretical studies employing other potential energy surfaces, and are also used to simulate experimental differential cross sections obtained from recent molecular beam measurements, which are partially resolved in the internal states of the products. The comparison provides evidence that excited electronic states do participate in the title reaction at 0.196 eV, but that their contribution, particularly that of the $A^{″}$ state, is overestimated by the quasiclassical trajectory (QCT) calculations employing the latest, and most accurate, potential energy surfaces.