Wave-packet propagation approach in the theory of charge transfer in projectile–metal surface interactions

Abstract

A brief review of the results obtained recently with the wave packet propagation method in the problem of resonant charge transfer (RCT) in collisions of atomic particles with metal surfaces is given. This method can be equally applied to the case of free-electron metal targets and to metal surfaces with a projected band gap. It provides a very transparent understanding of the one-electron processes occuring in such collisions. The new features of the RCT process due to the presence of a projected band gap for the electron motion along the normal to the surface are described for Li and H − projectiles colliding with a Cu(1 1 1) surface. It is shown that the decay of the resonance states located inside the band gap is strongly dominated by the 2D surface state continuum, while the decay into bulk Cu is strongly reduced. The resonance widths obtained for the metal with the projected band gap are, as a rule, significantly smaller than the widths in the corresponding jellium metal problem. These results provide new opportunities for theoretical investigations of the resonant charge transfer.