Helium scattering studies of the surface structure and dynamics of rare-gas crystals

Abstract

We review our experiments involving He scattering from the surfaces of ordered rage-gas overlayers physisorbed on Ag(111). The rare gases studied were Ar, Kr and Xe. The measurements were performed on thin-film structures which were grown on a layer-by-layer basis, from monolayer to thick film, in order to study how the surface properties changed with increasing distance from the substrate. Three types of experiments are discussed; elastic diffraction, selective adsorption and inelastic single-phonon scattering by angle-resolved time-of-flight. These experiments, taken together, provide a broad overview of the static and dynamic surface properties of rare-gas overlayers. They also provide information about the forces which govern the adatom–adatom and adatom–substrate interactions.