Hybridization of ionic levels at metal surfaces

We investigated the hybridization of He⁺, Li²⁺, and Be³⁺ ionic levels and the creation of surface resonances for nuclear charges $Z=2,3,$ and $4$ near an Al surface. Starting from a two-center basis set expansion with hydrogenic wave functions on the ion site and jellium wave functions in the metal half space, we calculate the self-energy for ion-surface system in the fixed-ion approximation. We obtain convergence by using a rather small set of bound ionic states. This ideally suits this method for the generation of adiabatic basis states that can be used in time-dependent close-coupling calculations for slow ion-surface collisions. We compare our resonance energies and widths with other theoretical approaches, discuss electronic density profiles, and analyze resonances in terms of Stark states.