Berlin 2008 – wissenschaftliches Programm
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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations
SYEC 2: Exact-exchange and hybrid functionals meet quasiparticle energy calculations II
SYEC 2.1: Vortrag
Donnerstag, 28. Februar 2008, 14:00–14:15, A 053
Range separated hybrid density functionals: the importance of middle-range Hartree-Fock exchange — •Artur F. Izmaylov1, Thomas M. Henderson1, Gustavo E. Scuseria1, and Andreas Savin2 — 1Department of Chemistry, Rice University, Houston, Texas 77005, USA — 2Laboratoire de Chimie Théorique, CNRS, Université Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris, France
In spite of the great success of regular hybrid density functionals, there are still at least two major problems with their application: first, they become computationally intractable when applied to small band-gap periodic systems, and second, properties that heavily depend on the right asymptotic behavior of the exchange-correlation potential suffer from the potential's wrong representation with hybrid functionals. In this work we show that both of these problems can be substantially resolved by introducing range separation of the Coulomb operator into short-, middle-, and long-range parts, and neglecting short- and long-range Hartree-Fock exchange contributions. We demonstrate how addition of middle-range Hartree-Fock exchange to the Perdew-Burke-Ernzerhof (PBE) functional affects thermochemistry and barrier heights in molecules, and band gaps, polarizabilities, and excitation energies in solids.