Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 57: Surface Chemical Reactions and Heterogeneous Catalysis II
O 57.2: Vortrag
Donnerstag, 29. März 2007, 16:00–16:15, H38
CO adsorption on a surface oxide: A combined DFT and XPS study — •Jutta Rogal1, Edvin Lundgren2, Jesper Andersen2, and Karsten Reuter1 — 1Fritz-Haber-Institut, Faradayweg 4-6, D-14195 Berlin, Germany — 2Department of Synchrotron Radiation Research, Institute of Physics, Lund University, Box 118, S-221 00 Lund, Sweden
CO adsorption at some transition metal and bulk oxide surfaces is a well-known showcase for the deficiencies of present-day exchange and correlation (xc) functionals in density-functional theory (DFT). Here we investigate whether similar problems in the determination of the proper adsorption site exist for CO adsorption on a so-called surface oxide, i.e. a nanometer thin oxide film. For this we focus on the (√5 × √5)R27∘ surface oxide at Pd(100) and combine DFT with high-resolution x-ray photoemission experiments. Comparing the calculated Pd 3d5/2 and C 1s surface core-level shifts with the experimental data allows to unambiguously identify the bridge site as the adsorption site populated in the experiment. While this is also the most stable adsorption site when using the local-density and several gradient-corrected xc functionals in the DFT calculations, the absolute values of the binding energy at this bridge site is found to vary significantly for the different xc functionals. Suitably combining the computed binding energies and diffusion barriers in kinetic Monte Carlo simulations provides finally first insight into kinetic limitations to the ordering behavior of the CO adsorbates under the low-temperature conditions of the experiment.