Theoretical energy distributions of atoms sputtered from elastic collision spikes by monomer and dimer ion bombardment

Abstract

The energy spectra of atoms sputtered from metal targets by bombardment with heavy monomer and dimer ions have been investigated on the basis of a standard model for elastic collision spikes. In particular we calculated the energy distributions for a Au sample bombarded by 4 keV I⁺ and 8 keV I ⁺₂ ions. The results were compared with the recent time of flight measurements performed by de Vries and coworkers. It was shown that the model described accurately most of the experimental observations: the count rates and the relative cascade to spike ratios for both I⁺ and I ⁺₂ projectiles, and the energy spectrum for dimer sputtering. The spectrum for monomer bombardment, however, was shifted towards lower energies in comparison to the experimental one. The possible source of this discrepancy is discussed.