Electron emission from the interaction of multiply charged ions with a Au(110) surface

Abstract

Abstract We measured electron energy distributions from the interaction of N+q and O+q (q = 5–7) at grazing incidence with a clean Au(110) surface. The acceleration voltage of 10 kV results in velocity components perpendicular to the surface which correspond to impact energies of a few hundred eV. The main source for the electronic particle-surface interaction is therefore the potential energy of the incoming projectile. For the experiment the Oak Ridge National Laboratory ECR source was used, the electron energy spectra were measured using a standard four-grid LEED Auger system. The same system served to control the surface structure and cleanliness. The results show evidence of kinetic electron emission and strong peaks at 250 eV for both N+6 and O+7 projectiles and peaks at 380 eV for N+6 and at 480 eV for O+7. With the lower charge states N5+ and O+6 no peaks are found. The results clearly indicate the important role of the K-shell hole in the interaction. We identify the higher-energy peaks as projectile KLL-like Auger decay from poorly defined upper states. The 250 eV peak is interpreted as Au NVV-like Auger emission, where the hole in the Au N shell is created by an interaction with the projectile K-shell hole.