ENERGY-LOSS OF LIGHT-IONS AND NEUTRALS FROM SURFACE SCATTERING

The energy spectra of He scattered at grazing incidence from a clean metal surface are measured by a time-of-flight method. The results are interpreted in terms of the dielectric response function of the metal. It is shown that surface effects and straggling have a major influence in the energy range under consideration (1-10 keV). There is also a basic connection between energy loss and charge state, such that these phenomena must be dealt with by the same formalism. It is shown that Auger neutralization is the dominating process and hence the energy loss depends on how long the incoming particle interacts with the surface as an ion or as a neutral. © 1990.