Theory of fast ion-surface collisions at grazing incidence: emission of electrons due to capture and loss to the continuum

Two mechanisms leading to the emission of electrons during the scattering of ions from a metal surface at grazing incidence are investigated. Emission probabilities are derived within a semiclassical approximation starting from first principles. For the capture of target electrons to the projectile continuum, first numerical results show three dominant features in the emitted electron spectrum. In addition to the Coulomb-cusp at zero relative velocity of electrons and projectiles, two structures with widths related to the Fermi energy of the metal conduction band are identified. They correspond to slow 'soft-collision' electrons and binary-encounter electrons, where the latter are most likely emitted at twice the projectile speed.