Electron emission during ion-surface interactions

Structures in electron spectra arising from low energy grazing incidence collisions of ions with single crystal metal surfaces are discussed. Peak-like structures in the kinetic emission spectra for the ion-surface systems H+/Al(1 1 1) and H+/Cu(1 1 0) - previously ascribed to plasmon excitation and decay by electron emission - are shown to be probably due to a two-step process: in the first step bulk Bloch-waves of electrons with wave vectors parallel to the surface and energies in the ionization continuum are populated by kinetic emission, and in the second step these Bloch-waves decay by scattering off the surface atoms, leading to interference effects in the scattered electron intensity