Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 21: Electronic Structure and Spin-Orbit Interaction I
O 21.1: Talk
Monday, March 11, 2013, 16:00–16:15, H42
A non-local density functional by explicitly modeling of the exchange-correlation hole in inhomogeneous systems — •Klaas J.H. Giesbertz1, Robert van Leeuwen2, and Ulf von Barth3 — 1Department of Theoretical Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands — 2Department of Physics, Nanoscience Center, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Survontie 9, Jyväskylä, Finland — 3Department of Mathematical Physics, Institute of Physics, Lund University, Sölvegatan 14A, Lund S-22362, Sweden
We develop a non-local density functional by a direct modeling of the shape of exchange-correlation (xc) hole in inhomogeneous systems. The functional is aimed at giving an accurate xc-energy and an accurate corresponding xc-potential even in difficult near-degeneracy situations such as molecular bond breaking. In particular we demand that: (1) the xc hole properly contains −1 electron, (2) the xc-potential has the asymptotic −1/r behavior outside finite systems and (3) the xc-potential has the correct step structure related to the derivative discontinuities of the xc-energy functional. These demands are achieved by screening the exchange hole in such a way that the pair-correlation function is symmetric and satisfies the sum-rule. These two features immediately imply (1) and (2) while the explicit dependence of the exchange hole on the Kohn–Sham orbitals implies (3). For the dissociating hydrogen molecule, we obtain much improved xc holes and thus also improved binding energies at different interatomic distances, as compared to the local density approximation.