Lifetimes of excited atoms near metal surfaces.

We present accurate calculations of the lifetimes and energy shifts of hydrogen and alkali atomic levels near a jellium metal surface. "Complex scaling" of the Schrodinger equation is employed to obtain directly the real and imaginary parts of the atomic resonance energies. Excited atomic levels shift differently with distance and there are many possibilities of level crossings. At such positions the hybridization can be strongly enhanced and lead to states that are oriented towards or away from the surface, with very different lifetimes and non- exponential decay of widths with distance from the surface. Previous calculations of the atomic level widths have not included these facts and typically have overestimated the level widths by several orders of magnitude. We discuss the qualitative consequences of our findings of longer lifetimes and extensive hybridization on the interpretation of neutralization processes in ion-surface collisions. Finally, we show that the presence of a weak lateral corrugation in the surface potential has a similar effect on neutralization as an increased surface temperature.