Gas-Surface Interactions Studied with Molecular Beam Techniques

Abstract

determina­ tions of the gas-surface physisorption potential for several systems have been obtained from surface resonant scattering. The interpretation of dif­ fraction intensities in terms of the geometric structure of the outermost exposed surface atoms now appears capable of being a quantitative struc­ tural tool. The dispersion of surface Rayleigh phonons has been com­ pletely determined for a few surfaces using atom scattering, to an accuracy which has required the theoretical spectrum to be recalculated. The coupling between rotational quanta and surface phonons has been characterized. The details of the average energy transfer between atomic gases and surfaces have been determined and successfully modeled. The partitioning among different scattering channels of particles that undergo energy exchange with surfaces has been studied, as have been the energy distributions of products of several chemical reactions on surfaces. Re­ cently developed techniques have been incorporated into the ultrahigh vacuum (UHV) arrangement normally required for fruitful study. These highlights and a large number of other informative studies with similar objectives form the subject of this review. In general the work surveyed has in common the utilization of molecular (atomic) beam techniques to characterize the details of elastic, inelastic, and reactive encounters of gases with surfaces. Other experimental work may be included if it is