Time-dependent wave packet and quasiclassical trajectory studies of the Au + HD reaction: competition between the reactive channels

Abstract

Time-dependent wave packet (TDWP) and quasiclassical trajectory (QCT) calculations are carried out for the Au (2S) + HD (X1∑+g) reaction. The reaction probabilities, integral cross sections (ICSs) and differential cross sections (DCSs) of the two reactive channels (AuH + D/AuD + H) are calculated. The ICS results indicate that the dominant reactive channel changes from AuD + H to AuH + D with the collision energy increasing. As is known from the distributions of the complex lifetime, this change mainly results from the difference between the direct reactive mechanisms in the two channels. With collision energy increasing, the growth of direct reactive collisions in AuH + D channel is much larger than that in the AuD + H channel. This is explained by the fact that, in the direct reactive mechanism with a small impact parameter, the D atom with a larger mass can get away easily from the potential well, and the H atom is likely to be captured by the Au atom. To compare vector properties of the two reactive channels, a study of the stereodynamics for the title reaction is also carried out by the QCT method. Due to more direct reactive collisions, product rotational polarization of the AuH + D channel is more obvious than that of the AuD + H channel.