Focusing Effects in Low-Energy Ion Scattering from Single Crystal Surfaces

Abstract
The angular distribution of low-energy K+ ions (250 to 1000 eV) scattered from a W(110) surface is studied as a function of polar angles of incidence and exit for various azimuths with a 127° electrostatic energy analyzer. For specific combinations of polar and azimuthal angles a strong enhancement of the intensity of certain peaks in the energy spectrum is observed which is attributed to focusing of ions scattered in the second layer by the atomic configuration of the first layer.