Statistics of ion-induced electron emission from a clean metal surface

Abstract

With a novel combination of experimental approaches, ion-induced electron emission from clean polycrystalline gold bombarded with (1–5 keV/amu) H+, H+2, and H+3 has been studied by measuring total electron yields, ejected-electron energy distributions, and, in particular, electron emission statistics (ES). Evaluation of ES included corrections for backscattering of electrons from the surface of the applied solid-state electron detector. By comparing ES for atomic and molecular ions of equal impact velocities, a negative molecular effect could be clearly demonstrated. This effect was further investigated by comparing measured ES for molecular ion impact with ES synthesized from measured ES for H+ and H+2 ion impact, respectively. The quality of approximating measured ES by Poisson and Polya statistical distributions was investigated in detail and found to be generally unsatisfactory.