Semiclassical stochastic trajectory investigation of vibrational-rotational-translational-phonon energy transfer: The role of attractive forces

A semiclassical stochastic trajectory (SST) approach to the study of collision induced transitions in gas molecule-solid surface scattering is used to investigate vibrational-rotational-transiational-phonon energy transfer in the H₂, D₂, HD-(smooth)Pt systems. State-to-state rotationally and ro-vibrationally inelastic transition probabilities are determined using interaction potentials with varying strength of the long-range attractive component. Rigid and non-rigid surfaces are considered, the latter via the generalized Langevin-ghost atom technique. The results demonstrate that addition of a significant attractive interaction broadens the rotationally and ro-vibralionally inelastic probability distributions. This leads in the latter case to the replacement of the near-resonant vibration-rotation mechanism for vibrational relaxation by a much more effective and uniform vibration-rotation, translation mechanism.