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O: Fachverband Oberflächenphysik

O 70: Gerhard Ertl Young Investigator Award

O 70.5: Vortrag

Donnerstag, 17. März 2011, 13:15–13:45, WIL C307

Towards accurate modeling of van der Waals interactions for surfaces and interfaces — •Alexandre Tkatchenko — Fritz-Haber-Institut der MPG, Berlin, Germany

Density-functional theory (DFT) is the method of choice for the modeling of properties and functions of surfaces and interfaces, typically yielding reasonable trends for strong chemical bonding. In the quest for a predictive method for interface modeling, the most pressing issue is thus an accurate description of the long-range van der Waals (vdW) interactions [1,2]. We have recently developed a set of efficient methods for an accurate description of intermolecular vdW interactions in DFT and MP2 theories [2,3]. When applied to the adsorption of nitrogen on graphite, our methods yield quantitative agreement with all experimentally measured data. Our PBE+vdW method also leads to accurate adsorption geometries for complex switches on metallic surfaces [4], as well as for the isophorone/Pd(111) system, where a balanced description of both the chemisorbed and the physisorbed state is essential. Despite these successes, the adsorption energies for molecules on metallic surfaces are systematically too large. The inclusion of screening effects inside the bulk by approximate methods leads to an improved agreement with experimental desorption enthalpies. The comparison of our theory with the non-local vdW-DF functional [1] and the many-body EX+cRPA method will be discussed. [1] M. Dion et al., PRL 92, 246401 (2004); [2] A. Tkatchenko and M. Scheffler, PRL 102, 073005 (2009); [3] A. Tkatchenko et al., JCP 131, 094106 (2009); [4] G. Mercurio et al., PRL 104, 036102 (2010).