General expressions for the self-energy of hydrogenic atoms near a metal surface have been derived. It is found that the self-energy at the metal surface saturates to a finite value with the inclusion of multipolar excitations of the hydrogenic atoms. Numerical results have been presented for hydrogenic atoms moving normal to the metal surface at two speeds. It is also found that dispersion effects of surface-plasmon excitation further reduce the magnitude of the self-energy.

• Received 27 February 1992

DOI:https://doi.org/10.1103/PhysRevB.46.7088