Lifetimes of rotational resonances in molecule-surface scattering quantum versus classical results

The lifetimes of rotationally-mediated resonances in the scattering of HD from a flat Ag surface are calculated by the quantum-mechanical complex rotation method and by classical trajectories. Qualitatively, considerable similarity is found between the quantum and the classical descriptions of the nature of the trapped states and of the mechanism of their decay. Quantitatively, quantum lifetimes are shorter than the corresponding classical values by as much as a factor of 4 to 7. Several interesting properties of the resonance states and trends associated with the lifetimes are observed, and simple physical interpretations offered.