Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Focus Session: Structure and Chemistry of Metal-Oxide Surfaces II
O 55.4: Vortrag
Mittwoch, 14. März 2018, 11:15–11:30, MA 005
Benchmarking DFT calculations for metal oxides: geometric adsorption site of copper and silver adatoms on magnetite — Matthias Meier1,2, Zdenek Jakub2, Jan Balajka2, Jan Hulva2, Roland Bliem2, Pardeep K Thakur3, Tien-Lin Lee3, Cesare Franchini1, Michael Schmid2, Ulrike Diebold2, Francesco Allegretti4, •David A Duncan3, and Gareth S Parkinson2 — 1University of Vienna, Vienna, Austria — 2Technical University of Vienna, Vienna, Austria — 3Diamond Light Source, Didcot, UK — 4Technical University of Munich, Munich, Germany
Single-site catalysis is a promising field for studying model catalytic reactions. However, to gain true insight into the inner workings of any system, it is necessary to be able to reliably model it with theoretical calculations, and to benchmark these calculations with stringent quantitative experimental constraints. In this work we utilised X-ray standing waves (XSW) to benchmark density functional theory (DFT) calculations of one such system: single adatoms on the Fe3O4(001).
Although the clean surface structure is known [1], the geometry of the adatoms has only been probed by non-quantitative techniques, which do not provide suitable benchmarks for theoretical calculations. The surface structure of Ag and Cu adatoms was directly determined by XSW to occupy the same lateral site at a height of 0.43 Å and 0.96 Å, respectively. The commonly used DFT+U formalisations overpredicted lattice constant, but underpredicted the adatom adsorption height, raising significant questions on its applicability to this system.
[1] R. Bliem, et al., Science 346, 1215 (2014);