9807410 Bruch This is a theoretical research grant on dynamical processes in physical adsorption. The goal is to achieve a quantitative understanding of the interactions of atoms and molecules with surfaces by treating conditions where highly complex problems can be separated into more manageable pieces. The research subjects include the structures and dynamics of atomically thin layers and the dynamical processes coupling the layers to the supporting substrate. Examples are chosen from recent inelastic helium scattering and sliding friction experiments. There continues to be a strong connection to the more traditional electron and X-ray diffraction experiments on adsorbed layers. %%% This is a theoretical research grant on dynamical processes in physical adsorption. The goal is to achieve a quantitative understanding of the interactions of atoms and molecules with surfaces by treating conditions where highly complex problems can be separated into more manageable pieces. The research subjects include the structures and dynamics of atomically thin layers and the dynamical processes coupling the layers to the supporting substrate. Examples are chosen from recent inelastic helium scattering and sliding friction experiments. There continues to be a strong connection to the more traditional electron and X-ray diffraction experiments on adsorbed layers. ***