Experimental and computational studies of positron-stimulated ion desorption from TiO2(1 1 0) surface

Abstract

Experimental and computational studies of the positron-stimulated O $^+$ ion desorption process from a TiO _2 (1 1 0) surface are reported. The measured data indicate that the O $^+$ ion yields depend on the positron incident energy in the energy range between 0.5 keV and 15 keV. This dependence is closely related to the fraction of positrons which diffuse back to the surface after thermalization in the bulk. Based on the experimental and computational results, we conclude that the ion desorption via positron-stimulation occurs dominantly by the annihilation of surface-trapped positrons with core electrons of the topmost surface atoms.

Keywords

• positrons
• ion desorption
• density functional theory (DFT)