Quantum scattering calculations of the O(1D) plus HCl reaction using a new ab initio potential and extensions of J-shifting

We report results of quantum wave packet calculations of the O(D-1)+HCl(v=0,j)--> ClO+H, OH+Cl, reactions for zero and nonzero total angular momentum, J, (using the centrifugal sudden approximation), and using a new fit to extensive ab initio calculations of a global potential [K. A. Peterson, S. Skokov, and J. M. Bowman, J. Chem. Phys. 111, 2445 (1999)]. Initial state-selected and cumulative reaction probabilities to form each set of products for J=0 are calculated by a direct summation of the initial state-selected reaction probabilities. We propose and test a simple energy-shifting approximation that relates the initial state-selected reaction probability for arbitrary j to the one for j=0. Extensions of standard J- and K-shifting methods are suggested and applied to both reaction channels. In doing this extension the adiabatic rotation approximation is used to determine the rotational barriers in the entrance and exit channels. The energy dependence of the reaction cross sections to form the two products is calculated for O(D-1)+HCl(v=0,j=0) using J- and K-shifting and compared at two translational energies to results of quasiclassical trajectory calculations. The thermal rate constants for the two reaction channels are calculated from 200 to 400 K and compared to experiment. (C) 2000 American Institute of Physics. [S0021-9606(00)00939-9].