Inner shell vacancies in sputtered atoms

Impact of heavy ions (Ne+, Ar+) on surfaces of Mg, Al and Si are known to produce Auger spectra characteristic of 2p vacancies in the target species. Excitation is largely by recoil collisions in the target matrix leading to curve crossing events. A detailed modelling of the observed spectrum is performed which accounts for all significant features. An underlying continuum is shown to be due to secondary electrons and to decay of atoms in the matrix. An apparent discrepancy between the high energy edge of electron and ion induced spectra is due to a hitherto unidentified line in the ion induced spectrum. Dominant line features of the ion-induced spectra are due to sputtered neutral atoms with a single L-shell vacancy. Electron conficurations and measured excitation energies are for Mg (2p53s23p) 50.6 eV, for Al (2p53s23p2) 73.8 eV and for Si (2p53s23p3) 101.1 eV. (orig.)