Ion Desorption from TiO_2 (110) by Low Energy Positron Impact

摘要

We have observed positron-stimulated ion desorption from a TiO_2 (110) surface. H+ and O+ ions were desorbed at incident positron energies above the desorption thresholds for electron impact. However, only O+ ions were detected at energies below those thresholds. These results suggest that by surface ionization positron annihilation as well as by positron impact leads to the O+ ion desorption. By contrast, it is likely that the H+ ions are not desorbed by positron annihilation, but rather by impact ionization.