Curve-crossing analysis for potential sputtering of insulators

We develop a theoretical model for the recently observed threshold for pote ntial sputtering of LiF by slow singly and doubly charged ions. The thresho ld coincides with the potential energy to create a cold hole in the valence band of LiF by resonant neutralization. We calculate the level shift of th e incident ion and the deformation of the valence band under the influence of the projectile. Resonant neutralization becomes possible for ions with r ecombination energies larger than 10 eV in agreement with the experimental findings. (C) 2000 Elsevier Science B.V. All rights reserved.