Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 52: Methods: Atomic and Electronic Structure II

O 52.2: Vortrag

Donnerstag, 29. März 2007, 11:30–11:45, H42

Towards excitation spectra for molecules on surfaces: quasiparticle energy calculations — •Xinguo Ren, Patrick Rinke, Volker Blum, and Matthias Scheffler — Fritz-Haber-Institut der MPG, D-14195, Berlin

To study adsorption-related changes in the electronic structure of molecules from first principles, it is highly desirable to have a computational scheme that can treat both confined (molecules) and extended systems (surfaces) efficiently on equal footing. For present-day excited-state formalisms, achieving this “equal footing" is a challenge. Based on a new highly efficient local-orbital DFT code [1], we have developed a local-orbital based formalism of the GW approximation for the many-body self-energy, allowing us to calculate the quasiparticle excitation energies of confined systems efficiently. Focussing on the description of isolated molecules we show for the example of benzene how different local exchange-correlation functionals (LDA, PBE) and non-local (hybrid) schemes (HF, PBE0) affect the atomic and electronic structures of the ground state. In a second step we demonstrate the influence of the ground state functional on the GW excitation spectrum and compare this to previous calculations [2].

[1] V. Blum, R. Gehrke, P. Havu, V. Havu, X. Ren, and M. Scheffler, The FHI Ab Initio Molecular Simulations (AIMS) project, Fritz-Haber-Institut, Berlin (2006).

[2] M.L Tiago and J.R. Chelikowsky, Solid State Commun. 136, 333 (2005).