Quantum reaction dynamics of O(3P)+HCl on a new ab initio potential energy surface

Abstract

Quantum reaction dynamics of O(3P)+HCl↔OH+Cl is studied by using a new ab initio potential energy surface calculated by Ramachandran et al. [J. Chem. Phys. 111, 3862 (1999)]. The hyperspherical elliptic coordinate approach is applied with an emphasis on elucidating reaction dynamics for J (total angular momentum quantum number)=0. In terms of the previously established concept that reactive transitions are nothing but vibrationally nonadiabatic transitions at important avoided crossings, clear interpretations are given for the following dynamical features: (i) reactivity depending on potential energy surface topography, (ii) final rotational state distributions for specified initial rovibrational states, and (iii) resonance structures appearing in some reactions. Thermal rate constants are approximately estimated from the present J=0 results by using the J-shift approximation. The present results are compared with our previous ones based on the different potential energy surface calculated by Koizumi–Schatz–Gordon (KSG). The calculated adiabatic potential energy curves of the present new surface have deep wells in the OH+Cl channel in contrast to the KSG potential energy surface. Consequently, the new surface leads to quite different dynamics from those on the KSG surface. Comparisons with the results obtained by quasiclassical trajectory calculations are also made.