ELASTIC AND INELASTIC-SCATTERING OF NEUTRAL ATOMS FROM SOLID-SURFACES

The influence of lattice dynamics on the neutral atomsurface scattering is considered from a quantum-mechanical point of view beyond the DWB approximation. The repulsive part of the atomsurface potential is assumed to be a hard corrugated wall. Exact equations are then presented for the gas atom wave function, by making use of the extinction theorem. In an approximation which turns out to be equivalent to the potential scattering approximation, we show that the temperature dependence of the elastic-scattering cross-section may be entirely written in terms of a Debye-Waller factor (DWF) if only long-wave-length phonons are important. In the framework of the theory we discuss Beeby's assumption about the form of the DWF and show that it holds whenever the adiabatic hypothesis for the atom-surface scattering is valid. © 1979 Società Italiana di Fisica.