Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 63: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles IV (jointly with TT)
O 63.2: Vortrag
Donnerstag, 29. März 2012, 11:00–11:15, HE 101
Renormalized second-oder perturbation theory for the electron correlation energy: concepts and benchmarks — •Xinguo Ren1, Patrick Rinke1, Gustavo E. Scuseria2 und Matthias Scheffler1 — 1Fritz-Haber-Institut der MPG, Berlin, Germany — 2Rice University, Houston, USA
We present a renormalized second-oder perturbation theory (R2PT) for the electron correlation energy that combines the random-phase approximation (RPA), second-order screened exchange (SOSEX) [1], and renormalized single excitations (rSE) [2]. These three terms all involve a summation of certain types of diagrams to infinite order, and can be viewed as a “renormalization" of the direct, the exchange and the single excitation (SE) term of 2nd-order Rayleigh-Schrördinger perturbation theory based on an (approximate) Kohn-Sham reference state. A preliminary version of R2PT has been benchmarked for covalently-bonded molecular systems and chemical reaction barrier heights [3] and shows an overall well balanced performance. We have extended this, by including “off-diagonal” diagrams into the rSE term and expect this refined version of R2PT to be more generally applicable to electronic systems of different bonding characteristics. Extended benchmarks of van-der-Waals-bonded molecules and crystalline solids will be presented. [1] A. Grüneis et al., J. Chem. Phys. 131, 154115 (2009). [2] X. Ren et al., Phys. Rev. Lett. 106, 153003 (2011). [3] J. Paier et al., arXiv:cond-mat/1111.0173.