Positron-annihilation-induced ion desorption fromTiO2(110)

Abstract

We have investigated the positron-stimulated desorption of ions from a ${\text{TiO}}_{2}(110)$ surface. Desorbed O${}^{+}$ ions were detected in coincidence with the emission of annihilation $\ensuremath{\gamma}$ rays. The energy dependence of the ion yields shows that the O${}^{+}$ ions were detected at energies much lower than the previously reported threshold for electron impact desorption corresponding to the excitation energy of Ti($3p$) core electrons. These results provide evidence that core-hole creation by positron annihilation with electrons in the core levels leads to ion desorption.