Effect of the surface track potential on electron emission in 60–100 keVH+grazing bombardment of LiF

Abstract

We have measured energy distributions of electrons emitted at forward angles during 60--100 keV ${\mathrm{H}}^{+}$ grazing bombardment of LiF surfaces. The electron energy spectra from the insulator are compared with those for Al(111), Si(111), and gas phase Ar. In the case of LiF, a broad peak appears with the maximum at an energy ${E}_{m}$ lower than the convoy electron energy ${(E}_{\mathrm{ce}})$. The absolute value of the energy shift $\ensuremath{\Delta}{E=E}_{m}\ensuremath{-}{E}_{\mathrm{ce}}$ increases with the ${\mathrm{H}}^{+}$ velocity, and depends on the sample topography. The results are discussed in terms of the attractive (track) and the repulsive surface-induced potentials.