Charge state dependence of the energy loss of slow nitrogen ions reflectedfrom an aluminum surface under grazing incidence

The experimentally observed monotonic increase of the energy loss with char ge q for Nq+ ions impinging on an Al(111) surface under grazing angle of in cidence is explained by a model that accounts for the effect of K- and L-sh ell vacancies in the stopping power. Our model allows us to estimate the ch aracteristic time scales (and distances from the surface) for the neutraliz ation and relaxation of multicharged ions. We use a transport cross section formulation of the electronic stopping of ions in an electron gas, as well as a self-consistent calculation of the scattering potential within densit y functional theory. (C) 1999 Elsevier Science B.V. All rights reserved.