The interaction of O with line defects of Ti interstitials on a TiO2(110) surface was investigated by using scanning tunnelling microscopy measurements and first-principles calculations. First-principles molecular dynamics calculations showed that an O molecule dissociatively adsorbed on a row of Ti interstitials. Oxygen atoms subsequently surrounded a Ti interstitial to form the equatorial plane of a partially complete octahedron: a basic building-block for single- and double-strand formation. Upon exposure of single strands to O at room temperature, bright spots agglomerated preferentially on, and along, strands. The scanning tunnelling microscopic images of the bright spots, interpreted using density functional theory, indicated that they were TiOx (x < 2) aggregates, and that strands could serve as nucleation sites for surface growth.

Reoxidation of TiO2(110) via Ti Interstitials and Line Defects. Park, K.T., Pan, M., Meunier, V., Plummer, E.W.: Physical Review B, 2007, 75[24], 245415