Interaction of molecular hydrogen ions with the LiF(100) surface - art. no. 045411

Scattering of II: molecules from a LiF(100) surface at grazing incidence is studied in the energy range from 600 to 4000 eV, The scattered particle yi eld measured in an azimuthal scan at various temperatures showed peaking at the [(1) over bar 00] direction. A W-shaped peaked yield was observed near the [(1) over bar 00] direction above a temperature of about 200 degreesC, which shows that there is no charging up of the LiF crystal at this temper ature. About 70% molecular survival was obtained at a very low primary ener gy of about 600 eV and this dropped to about 20% around 1300 keV. At low H- 2(+) energies a very low charge state fraction H+ and H- ions were observed and it reached a maximum to about 15%, and 10%, respectively, around 2 - 2 .5 keV and decreased at higher energies. The molecular survival fraction an d the charge state fractions stabilize above 250 degreesC. The molecular su rvival fraction was found to be higher at a random condition when compared to the yield at the [(1) over bar 00] axis. The mean energy loss of the neu tral atoms is found to increase linearly with energy.