A COMPUTER-SIMULATION STUDY ON HYPERTHERMAL ENERGY RARE-GAS ION-SCATTERING FROM SOLID-SURFACES

Scattering of rare gas beams from solid surfaces at hyperthermal energ ies is studied by molecular dynamics simulations. The energy-angle dis tributions of He, Ne and Ar particles scattered from an oxygen-covered Rh(111) surface are calculated. The beam energy is varied in the ener gy range 5-50 eV and normal incidence is assumed. When the projectile is much ligther than the surface atoms, the profile of the energy-angl e distribution changes drastically due to the topographic change in th e equi-potential energy surface in this energy range. The distribution is sharp at low energies corresponding to binary collisions with a co rrugated surface, while it becomes very broad at high energies because particles penetrate the surface causing multiple collisions. On the o ther hand, the distribution is always broad and insensitive to the col lision energy when the mass of the projectile is greater than or equal to that of the surface atoms.