Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 95: Metal Substrates: Adsorption of Atoms and Inorganic Molecules
O 95.10: Vortrag
Donnerstag, 23. März 2017, 17:30–17:45, WIL A317
Crystallographic Structure of the Oxidized Rh(100) Surface — •Tilman Kisslinger, Pascal Ferstl, M. Alexander Schneider, and Lutz Hammer — Lehrstuhl für Festkörperphysik, Universität Erlangen–Nürnberg, D–91058 Erlangen, Germany
In this study we combine quantitative LEED–IV, STM and DFT calculations to reinvestigate the adsorption behavior of oxygen on the Rh(100) surface in the coverage regime up to 0.67 ML.
In this range three distinct phases exist: A (2 × 2)–O [1], a (2 × 2)–2O [2] and a (3 × 1)–2O structure [3]. The proposed models of these phases are verified by low R–factors between 0.07 and 0.10. For the (2 × 2)–O phase we corroborate the hollow site adsorption with additional 13 parameters determined. In case of the (2 × 2)–2O structure the clockwise-/ anticlockwise reconstruction of the substrate is confirmed. However, contrary to [2] our LEED analysis correctly accounts for all symmetry elements observed in experiment. It turned out that this does not change the structural parameters significantly, but alters the interpretation of the underlying physical processes. Instead of statistically disordered domains a statistical occupation of adjacent threefold coordinated sites by oxygen is the result of our structure determination (RP = 0.098). Regarding the (3 × 1)–2O phase the proposed model by Gustafson et al. is validated with structural parameters similar to those of the Pt75Rh25(100)–(3 × 1)–2O structure [4].
[1]: Oed et al., Surf. Sci. 207, 55 (1988) [2]: Baraldi et al., Phys. Rev. Let. 82, 4874 (1999) [3]: Gustafson et al., J. Phys. Cond. Mat. 24, 225006 (2012) [4]: Sporn et al., Surf. Sci. 416, 384 (1998)