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O: Oberflächenphysik

O 31: Oberflächenreaktionen II

O 31.6: Vortrag

Donnerstag, 11. März 2004, 12:30–12:45, H36

Vibrational Analysis of the V ₂ O ₅ (010) Surface with and without Oxygen Vacancies: ab-initio DFT Cluster Studies — •Christoph Friedrich and Klaus Hermann — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin

While the catalytic behavior of vanadium oxide has been known and utilized for a long time many microscopic details of oxidation reactions at vanadium oxide surfaces are still not fully understood. V₂O₅ reduces quickly when exposed to X-ray and LEED beams. It has been shown that under catalytic reaction conditions oxygen vacancies are always present on the surface and may act as active sites. From vibrational spectra obtained e.g. from Infrared and Raman-spectroscopy as well as HREELS measurements information about the geometry and bond strengths of the different vibrating species can be gained. Vibrational frequencies are particularly sensitive to changes in the local geometric and chemical environment. This work focuses on how the vibrational spectra are modified by the presence of different types of oxygen vacancies at the surface. In addition, the influence of adsorbed CO on surface vibrations is discussed.

This work is supported by SFB 546 “Structure, Dynamics, and Reactivity of Transition Metal Oxide Aggregates”.