Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 24: Electronic-Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - II
HL 24.11: Talk
Monday, March 20, 2017, 17:45–18:00, GER 38
Benchmark calculations of the electronic structure for molecules from the second-Born self-energy — •Michael Schüler1 and Yaroslav Pavlyukh1,2 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany — 2Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, P.O. Box 3049, 67653 Kaiserslautern, Germany
The non-equilbrium Green’s function (NEGF) formalism provides a state-of-the-art tool for modeling modern spectroscopic experiments. In particular, time-dependent problems can be treated based on the Kadanoff-Baym equations. The underlying approximation to the self-energy has to be consistent with the treatment of the initial state - as captured by the Matsubara formalism - in order to guarentee the basic conservation laws. One of simplest non-trivial approximation to the self-energy is the second-Born approximation (2BA), which has been employed in numerous time-dependent studies. Systematic tests on the accuracy of the 2BA for various molecules has, however, been lacking so far. In our contribution we fill this gap by benchmark calculations for the 2BA for small molecules from the well established G2 test set. We demonstrate that the accuracy of the 2BA for predicting ionization potentials and electron affinities can compete with accurate quantum chemistry methods such as the Møller-Plesset perturbation theory and the coupled-cluster method. We also apply our method to a class of larger molecules, the diamonoids, which are in the focus of recent experiments and theoretical studies.