Interaction potential for fast Ne atoms in front of LiF(001) surface

Fast Ne atoms with energies from 3 to 70 keV are scattered under a grazing angle of incidence from a flat and clean LiF(001) surface. For scattering along low-index directions (axial surface channeling) we observe pronounced peaks in the angular distributions of scattered projectiles which can be attributed to rainbow scattering. On the basis of classical trajectory calculations we derive from the rainbow angles the effective interaction potential of Ne atoms in front of LiF(001) and the underlying interatomic pair potentials in the eV energy range. Fair agreement with the data is found for individual pair potentials calculated from Hartree-Fock wave functions where the charge state of Li and F in the ionic crystal is taken into account.