Time-dependent quantum wave packet dynamics of S + OH reaction on its electronic ground state

Abstract

Initial state-selected dynamics of the S(³P) + OH (X²Π) → SO (X³Σ^–) + H (²S) reaction on its electronic ground potential energy surface (X̃²A″) is investigated here by a time-dependent wave packet propagation (TDWP) approach. Total reaction probabilities for the three-body rotational angular momentum up to J = 138 are calculated to obtain converged integral reaction cross sections and state-specific rate constants employing the centrifugal sudden (CS) approximation. The convergence of the latter quantities is checked by varying all parameters used in the numerical calculations. The cross section and rate constant results are compared with those available in the literature, calculated with the aid of the quasi-classical trajectory method on the same potential energy surface. Reaction probabilities obtained with the TDWP approach exhibit dense oscillatory structures, implying formation of a metastable quasi-bound complex during the collision process. The effect of rotational and vibrational excitations of reagent OH on the dynamical attributes is also examined. While the rotational excitation of reagent OH decreases the reactivity, its vibrational excitation enhances the same.