Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Ab-initio approaches to excitations in condensed matter I
O 41.6: Vortrag
Mittwoch, 25. März 2009, 16:15–16:30, SCH 251
Exploring the random phase approximation: application to CO adsorption, bulk metals, and weakly bonded molecules — •Xinguo Ren1, Patrick Rinke1,2, and Matthias Scheffler1,2 — 1Fritz-Haber-Institut der MPG, D-14195 Berlin, Germany — 2Materials Dept., UC Santa Babara, CA 93106, USA
Density-functional theory (DFT) within the generalized gradient approximation (GGA) has been immensely successful in describing the ground state properties of a diverse range of materials. However, inherent strong self-interaction effects and the absence of van der Waals (vdW) interactions are two prominent examples of GGA’s failures. These severely affect the description of (bio)molecules and in certain cases (e.g. CO) their adsorption on (transition)metal surfaces. Many-body perturbation theory in the random phase approximation (RPA) presents a promising way to go beyond GGA since it is expected to perform well for molecular, metallic and vdW systems alike. However, despite the recent interest the RPA has generated, a comprehensive assessment of its performance is not available. Using CO@Cu(111), a selection of bulk metals, and the benzene dimer, a prototypical π-conjugated system, as examples, we demonstrate the performance of the RPA for different types of systems. We show that the potential-energy surface of CO adsorbed on Cu(111) can be correctly described within RPA at a quantitative level. The binding energy of the benzene dimer, on the other hand, is considerably underestimated. We further show that these RPA results are not sensitive to the DFT functional chosen for the description of the unperturbed system.