EFFECT OF THE SURFACE TRACK POTENTIAL ON ELECTRON-EMISSION IN 60-100 KEV H+ GRAZING BOMBARDMENT OF LIF

We have measured energy distributions of electrons emitted at forward angles during 60-100 keV H+ grazing bombardment of LiF surfaces. The e lectron energy spectra from the insulator are compared with those for Al(111), Si(lll), and gas phase Ar. In the case of LiF, a broad peak a ppears with the maximum at an energy E-m lower than the convoy electro n energy (E-ce). The absolute value of the energy shift Delta E=E-m -E -ce increases with the H+ velocity, and depends on the sample topograp hy. The results are discussed in terms of the attractive (track) and t he repulsive surface-induced potentials.