Electron emission induced by grazing impact ofH+andHe+ions on a Cu(001) surface: Low-energy electron diffraction study

Abstract

Electron emission induced by ${\text{H}}^{+}$ and ${\text{He}}^{+}$ ions with energies up to 30 keV is studied for grazing impact on a clean and flat Cu(001) surface by making use of electron diffraction effects. Depending on the azimuthal orientation of low index directions in the crystal surface with respect to the projectile beam, we observe intensity spots in the angular distributions of emitted electrons. The data are analyzed in the framework of electron diffraction at the ordered surface and reveal interesting details on the emission and coherence mechanisms for the excitation of conduction electrons by fast atomic projectiles in the surface region of a metal.