Recent developements in charge-transfer theory

In this paper we discuss some recent theoretical developments of importance in the area of charge transfer between atoms and surfaces. Using the complex scaling method we have calculated the energy shift and broadening of atomic levels near metal surfaces. Two novel applications will be discussed. The first concerns the interaction of atomic Rydberg levels with clean metal surfaces. It is shown that as Rydberg atoms approach a surface, strong hybridization occurs that depends sensitively on both the atom-surface separation and the details of the surface potential. The widths of the hybridized states can differ by several orders of magnitude depending on their orientation with respect to the surface. The second application is an investigation of how dielectric overlayers adsorbed on metal surfaces can influence the energy shift and broadening of atomic levels. The calculations show that the energies and widths of atomic levels near metal surfaces can be influenced strongly by thin dielectric films adsorbed on the surface.