Evidences of a double resonant ionization mechanism in sputtering of metals

Abstract: We present a theory of resonant charge exchanges, between sputtered atoms and metal surfaces, in which surface effects occur as quasi-molecular correlations in the diatomic systems formed, in the collision cascade, between secondary emitted atoms and their nearest-neighbor substrate atoms that have provided the last impulse for ejection. We set up a generalized Anderson–Newns Hamiltonian, from first principles, using a truncated and orthonormal set of states obtained from the valence orbitals of the diatomic system and from a continuous basis of jellium wave functions. We calculate the one-electron matrix elements appearing in the equations of motion for the annihilation operators of the truncated set in comparison with those resulting from the basic theoryof resonant charge transfer. We determine the ionization probability of secondary emitted atoms versus their final emission velocities and we find it to be in good agreement with experimentallyderived data on the Cu+/C...