Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 62: Metal Substrates: Adsorption of Inorganic Molecules
O 62.7: Vortrag
Donnerstag, 28. Februar 2008, 11:00–11:15, MA 042
Towards a full undertanding of the “CO Adsorption" puzzle: advanced many-body electronic structure calculations of CO-adsorbed Cu custers — •Xinguo Ren1, Patrick Rinke2, and Matthias Scheffler1,2 — 1Fritz-Haber-Institut der MPG, 14195 Berlin, Germany — 2Materials Reserach Lab, University of California at Santa Babara, CA 93106
Density functional theory, within its present-day local/semi-local approximations (LDA/GGA), has known difficulties for describing certain surface chemical processes. For instance, for a CO molecule adsorbed at the Cu(111) surface, both LDA and GGA predict the wrong adsorption site, favoring the threefold-coordinated hollow site rather than the onefold-coordinated top one [1]. The energetic order of these two adsorption sites can be correctly reversed by applying a “local XC correction" scheme [2], in which an exchange-correlation (XC) energy correction can be obtained by using an improved XC treatment for relatively small clusters. However, such single-point total energy calculations do not reveal the underlying mechanism behind the improved description. To shed new light on the “CO adsorption puzzle" we have performed quasiparticle energy calculations for CO adsorbed on selected Cu clusters in second-order Møller-Plesset perturbation theory and the GW approach. The resultant energy spectra are analyzed in terms of charge transfer and energy level shifts with respect to LDA/GGA. [1] Feibelman et al., J. Phys. Chem 105, 4018 (2001). [2] Q.-M. Hu, K. Reuter, and M. Scheffler, Phys. Rev. Lett 98, 176103 (2007); 99, 169903(E) (2007).