Grazing collisions of swift protons with insulator surfaces

M.S. GRAVIELLE; I. ALDAZABAL; A. ARNAU; V.H. PONCE; J.E. MIRAGLIA; F. AUMAYR; S. LEDERER; H. WINTER

Alemania

Conferencia; XXV International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC); 2007

International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC)

We study theoretically and experimentally electron emission produced by grazing scattering of fast protons from LiF, KCl and KI crystal surfaces. These materials are typical broad band-gap insulators with a narrow valence band, which indicates that valence electrons retain essential parts of their atomic character. By analyzing the charge state of the projectile along the trajectory we conclude that the main mechanism of electron emission is the direct ionization of the surface induced by the bare ion. To describe this process we propose a theoretical model that makes use of the local character kept by valence electrons, representing the electronic transitions induced by the projectile along its path as a succession of single collisions with the surface ions [1].