Double-resonance photo-ionization of metal atoms: a sensitive probe of electronic processes during sputtering

This contribution deals with double-resonant photo-ionization schemes, involving auto-ionizing states, of Co, Ni, Cu, Sr, Ag and Ir metal atoms. The continuum structure around the first ionization limit of these atoms was explored, resulting in the identification of a large number of auto-ionizing states. The saturation behavior of double-resonant ionization schemes for the atoms in the ground state as well as in several metastable states was studied, and photo-ionization cross sections were derived. These highly efficient ionization schemes were applied in ion beam sputtering studies, which resulted in the identification of the dominant electronic process governing the emission of neutral atoms.