THERMAL-STABILITY OF ESD OF O+ IONS EJECTED FROM TIO2(110)

We present an investigation of the thermal stability of ESD of O+ ions from the TiO2(110) surface and using AES as a complementary technique . ion kinetic energy distributions of the ejected species with maxima at 4 and 7.5 eV - previously identified with ions ejected from the O i n-plane and the bridging O ligand, respectively - are very sensitive t o the thermal treatment of the surface. The intensify of both surface ions depends on the incident electron energy. In general, the ion yiel d tends to present two maxima at 400 and 700 K, the second one is also shown by the Ti(LMO(VB))/Ti(LMV) ratio as a function of temperature. These facts reveal significant changes of the surface structure charac terised by modifications of the population of the O in-plane and bridg ing O ligand. Annealing the surface at temperatures higher than 700 K decreases the intensity of both ion species up to 900 K. AES experimen t indicates that above 900 K the inter- to intra-atomic ratio tends to increase.