Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.2: Poster

Friday, March 4, 2005, 17:00–20:00, Poster TU D

Density-functional theory study of oxygen adsorption at vicinial Pd surfaces — •Yongsheng Zhang, Jutta Rogal, and Karsten Reuter — Fritz-Haber-Institut, Faradayweg 4-6, D-14195 Berlin

The contact with our O-rich atmosphere can lead to the formation of oxides at transition metal surfaces, and therewith significantly alter the surface properties and functionality. Although atomic steps are generally believed to play a prominent role in this oxide formation process, most of our atomic-scale understanding derives to date from studies concentrating on low-index surfaces. As a first step to explicitly address the effect of atomic steps, we use density-functional theory to investigate the adsorption of oxygen at vicinal Pd(11N) surfaces (N=3,5,7), exhibiting (111) steps and (100) terraces of varying width. Oxygen adsorption close to the steps induces strong changes in the geometric relaxation of the surfaces, that before followed a clear trend with contraction of all surface layers with undercoordinated atoms. Adsorption at the steps is energetically preferred compared to the terrace sites, and we find the geometric, energetic and electronic properties of the center terrace sites at Pd(117) to be already almost indistinguishable from those at a low-index Pd(100) surface.