COLL 74 |
| Wahlström Erik1, Ebbe K. Vestergaard1, Renald Schaub1, Anders Ronnau1, Jesper Matthiesen1, and Flemming Besenbacher2. (1) Interdisciplinary Nanoscience Center at University of Aarhus, Department of Physics, University of Aarhus, Ny Munkegade, DK-8000 Aarhus, Denmark, (2) Interdisciplinary Nanoscience Center, CAMP and Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, Aarhus, DK-8000, Denmark |
| Defects such as oxygen vacancies often dominate the chemical properties of transition-metal oxide surfaces. Recent studies on a prototypical model oxide surface - rutile TiO2(110) – will be presented, where time-resolved, variable-temperature scanning tunnelling microscopy has been exploited to study oxygen vacancies and their interaction with oxygen molecules as well as Au atoms. The interaction between oxygen vacancies has been investigated, revealing strongly anisotropic, repulsive long-range lateral forces. A surprising O2-mediated diffusion mechanism of oxygen vacancies will be presented. The diffusion of adsorbed O2 will be shown to proceed through charge transfer induced dynamics from conduction band electrons of the substrate. Bridging oxygen vacancies are found to be active nucleation sites for Au clusters and we find that each vacancy site can bind 3 Au atoms on average. Finally, the change in morphology of the gold nano-clusters, exposed to CO and O2, both under UHV and high pressure will be discussed. |
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Nanoscience and Nanotechnology
2:00 PM-5:15 PM, Sunday, March 28, 2004 Marriott -- Grand Ballroom K, Oral
Division of Colloid and Surface Chemistry |