Computer simulation of image acceleration of highly charged xenon ions in front of a metal surface

Using the time-evolution BC code, DYACOCT, we investigate the image acceleration of Xeq+ ions (q = 1-33) with energies 3.7 q keV which are scattered under a grazing angle of incidence from an Al (111) surface. We solve the coupled rate equations of the population P-n of the nth shell of the projectile, where electron capture, electron loss, Auger deexcitation and peeling-off process are explicitly included. For surface scattering of Xe-q+, we determine the screening lengths of highly charged Xe ions interacting with surface atoms, based on those electron distributions. The calculated image energies were compared with the experimental works of Winter et al., and we got the reasonable agreement with the experimental image energies for q<25. The discrepancy between simulation and experiment is found for q>25. This discrepancy is mainly due to the breakdown of the assumption employed in the experiment that the surface scattering is always the specular reflection. (C) 1999 Elsevier Science B.V, All rights reserved.