Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)
O 36.76: Poster
Montag, 7. März 2005, 15:00–18:00, Poster TU F
Van der Waals interaction: Semi-ab initio description of graphite and its surface — •Frank Ortmann, Wolf G. Schmidt, and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1,07743 Jena, Germany
Graphite is one of the most interesting and demanding model systems for ab initio calculations because of the strong sp2 -hybridized intralayer bonds and the weak van der Waals bonded layers. Density-functional calculations within the generalized-gradient approximation (DFT-GGA) fail to yield a converged lattice constant perpendicular to the graphene sheets[1].
Therefore we investigate the influence of an additional long-range attractive term based on the London description of van der Waals forces[2]. It is found that one obtains the correct c lattice constant of graphite while the changes of the bulk properties of diamond due to the inclusion of the van der Waals term are negligible. Results for the relaxation of the graphite surface will be presented.
[1] K. R. Kganyago and P. E. Ngoepe, Molecular Simulation 29, 39 (1999)
[2] F. London, Z. Phys. Chem. Abt. B11, 222 (1930)