Observation and destruction of an elusive adsorbate with STM: O₂/TiO₂

الأصل · EN

When a slightly defective rutile TiO₂(110) surface is exposed to O₂ at elevated temperatures, the molecule dissociates at defects, filling O vacancies () and creating O adatoms () on rows. The adsorption of molecular O₂ at low temperatures has remained controversial. Low-Temperature Scanning Tunneling Microscopy (LT-STM) of O₂, dosed on TiO₂(110) at a sample temperature of ≈ 100 K and imaged at 17 K, shows a molecular precursor at as a faint change in contrast. The adsorbed O₂ easily dissociates during the STM measurements, and formation of 's at both sides of the original is observed.