Electronic excitations in solids during impact of atomic particles

One- and two-electron non-adiabatic models of ion formation in sputtering a re briefly reviewed and compared with experiments on ion emission from Cu a nd from GaAs. Using these examples it is shown that in order to explain the experiments the models must be extended and must include substrate excitat ions described tentatively by an electronic temperature. Such approach allo ws for a consistent elucidation of the experimental data. Possible conseque nces of many-electron excitation processes for electron emission from bomba rded solids are also considered. (C) 2000 Elsevier Science Ltd. All rights reserved.