Contribution of kinetic and potential emission to keV singly charged ion-induced electron emission from a metal surface

A Monte Carlo simulation model of kinetic emission (KE) of electrons from a gold surface due to impact of He+ and Ar+ ions is combined with a model of potential emission (PE) due to the Auger neutralization of the projectile ions. The emphasis is placed on the energy distribution and emission statistics of electrons, as well as the total electron yield, in the keV impact energy range where KE and PE contribute with comparable importance to the electron yield. At low impact energies, PE dominates the electron yield, which decreases (increases) with increasing energy of He+ (Ar+) ions. With the onset of KE, the electron yield due to He+ impact begins to increase, and with further increase in energy, KE dominates the electron yield. This causes large changes in the peak energy and the shape of the energy distribution of emitted electrons. For Hei impact, the calculated emission statistics deviate from the observed statistics, whereas for Ar+ impact, a reasonable agreement between them is obtained.