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O: Fachverband Oberflächenphysik

O 22: Theoretical methods

O 22.8: Vortrag

Montag, 14. März 2011, 19:00–19:15, WIL C107

Wavefunction-based correlation method for metals: from bulk to surfaces and interfaces — •Elena Voloshina and Beate Paulus — Institut für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany

Theoretical determination of surface energies is a great challenge. While density functional theory (DFT) provides understanding of qualitative trends, absolute values depend strongly on the choice of the functional. An alternative approach with the advantage of the possibility of a systematical improvement are the wavefunction-based methods. One problem here is that a very accurate treatment, e.g. with the coupled-cluster method, scales very unfavorably with the number of electrons in the system. For this reason the method of increments was invented to calculate the correlation energy of bulk metals in terms of contributions from localized orbital groups [1,2]. This approach can be extended to system of low dimensionality, like surfaces. Furthermore, the method of increments is useful when considering surface adsorption phenomena, since DFT often fails to describe physisorption correctly. To demonstrate our approach we selected Mg(0001) surface, where the method of increments is used to calculate surface energy as well as Xe adatom interaction energy.

[1] E. Voloshina, N. Gaston, and B. Paulus, J. Chem. Phys. 126, 13411(2007); [2] E. Voloshina and B. Paulus: Phys. Rev. B 75, 245117 (2007); Chem. Modell. 6, 162 (2009); Z. Phys. Chem. 224, 369 (2010).