Structure effects in low-energy electronic stopping

Abstract

Recent experiments have shown electronic stopping cross-sections to have an oscillatory dependence on ionic atomic numbers with minima in the region of Li, Na and Cu. The amplitudes of the oscillations are enhanced when the ions are channelled. To explain these effects we have modified the Firsov theory of electronic stopping by replacing the Thomas-Fermi atom with simple Hartree-Fock wave functions, thus allowing for the different ionic sizes. Theoretical predictions are made for the stopping cross-sections of ions in amorphous carbon and of channelled ions in silicon.