TIME-DEPENDENT MEAN-FIELD APPROACH TO MOLECULE SURFACE SCATTERING AT FINITE TEMPERATURES

Theories are presented for the phonon inelastic scattering of molecules from surfaces. Both the molecule and the surface and bulk vibrations of the solid are treated in a fully quantum mechanical fashion. The models can include one- or multiphonon interactions and are thus applicable to both heavy and light gas species at both high and low beam energies. The method is a mean-field approach in that both the molecule and the bath are evolved simultaneously and self-consistently. The result is that the molecular wavefunction obeys a Schrodinger-like equation, but propagates on a gas-surface interaction potential which is both time- and temperature-dependent. The theory is easily implemented using spectral grid or semiclassical time-dependent scattering techniques, with only a small increase in computer requirements. The model is extended to the specific cases of atom- and diatom-metal scattering. Results are presented for H2, HD, D2, He, Ne and Ar scattered from metal surfaces.