Impact parameter dependence of electronic and nuclear energy loss of swiftions: H+ -> He and H+ -> H

In this paper we report the calculation of impact parameter dependent energ y losses of protons on hydrogen and helium for projectile energies from a f ew eV/amu up to 900 keV/amu using electron-nuclear dynamics (END). In each case it is found that, for smaller impact parameters, there is an initial r ise in energy deposition at low projectile energies due to nuclear stopping . At somewhat larger energies, the nuclear contribution decreases, and the energy loss is primarily due to electronic stopping. As the ionization chan nel is not explicitly open in these calculations, these results are somewha t below experimental results at energies above the ionization threshold. Ag reement with other calculations and the scanty experimental evidence is goo d. (C) 2000 Published by Elsevier Science B.V. All rights reserved.