Stereodynamics of rotationally inelastic scattering in cold He+HD collisions
Abstract
Stereodynamics of cold collisions has become a fertile ground for quantized studies of molecular collisions and control of the collision outcome. A benchmark process for stereodynamic control is rotational transition in He+HD collisions. This process was recently probed experimentally by Perreault et al. by examining quenching from j=2 to j'=0 state in the v=1 vibrational manifold. Here, through explicit quantum scattering calculations on a highly accurate ab initio interaction potential for He+H2, we reveal how a combination of two shape resonances arising from l=1 and l=2 partial waves controls the stereodynamic outcome rather than a single l=2 partial wave attributed in the experiment. Further, for collision energies below 0.5 cm-1, it is shown that stereodynamic preference for integral cross section follows a simple universal trend.