PGI-1 Seminar: Prof. Dr. Andreas Görling
Accurate density-functional methods based on correlation energy functionals within the exact-exchange random phase approximation
- 15 Dec 2011
- 10:00 PGI-Hörsaal
Lehrstuhl für Theoretische Chemie, Universität Erlangen-Nürnberg
Density-functional methods that treat the correlation energy within the random phase approximation (RPA) are discussed. A correlation functional that is termed EXXRPA (exact-exchange random phase approximation) and is obtained with the exact frequency-dependent exchange kernel via the fluctuation dissipation theorem is presented. The corresponding EXXRPA method can treat Van-der-Waals interactions and can correctly describe electron pair bonds in the dissociation limit without the need to resort to symmetry breaking in spin
space, i.e., the method is able to describe static correlation. Because the functional also yields more accurate electronic energies for molecules in their equilibrium geometry than standard correlation functionals, it combines accuracy at equilibrium bond distances and in dissociation processes with a correct description of spin, something all commonly employed correlation functionals fail to do. The use of auxiliary basis functions within the resolution-of-identity approach to reduce the computational effort of EXXRPA
methods is discussed.