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P. Varga:
"Formation and Reduction of Surface Oxides Studied on the Atomic Scale";
Vortrag: Seminar Institut für Allgemeine Physik (IAP), TU Wien; 11.08.2005.

The most frequently studied model systems in heterogenous catalysis are metal clusters deposited on ultra-thin oxide layers used as support. The thin oxide layers (which are conductive) are of great importance since they make it possible to use conventional surface science techniques while at the same time having the same or similar chemical properties as ceramic support materials of industrial catalysts. It has been shown recently that not only the metal cluster but also the oxide support itself play a decisive role in catalytic reactivity.
In the last few years we have determined the structure of several surface oxides formed on Ru, Pd, Rh and AlNi surfaces by using STM (scanning tunneling microscopy), in collaboration with G.Kresse (Univ.of Vienna), who did DFT based calculations (VASP-Vienna ab-initio simulation package), and E.Lundgren (Lund Univ., Sweden) who did HRCLS (high resolution core level spectroscopy). In this talk the structure of the alumina films grown at NiAl(110) will be presented [1] as well as the structure and stability of the surface oxide grown on Rh(111) at high oxygen exposure[2,3].

[1] G.Kresse, M.Schmid, E.Napetschnig, M.Shishkin, L.Köhler, P.Varga, Science 308 (2005) 1440
[2] J.Gustafson, A.Mikkelsen, M.Borg, E.Lundgren, L.Köhler, G.Kresse, M.Schmid, P.Varga, Y.Yuhara, X.Torrelles, C.Quiros, J,N,Andersen, Phys.Rev.Lett. 92(2004)126102
[3] E.Lundgren, J.Gustafson, A.Resta, J.Weissenrieder, L.Köhler, G.Kresse, J.Klikovits, A.Biedermann, M.Schmid, P.Varga, J.Electron Spectrosc.Relat.Phen. 144-147 (2005) 367