System-adapted correlation energy density functionals from effective pair interactions

Abstract

This article discusses some ideas concerning an ‘average-pair-density functional theory’, in which the ground-state energy of a many-electron system is rewritten as a functional of the spherically and system-averaged pair density. These ideas are further clarified with simple physical examples. Then it is shown that the proposed formalism can be combined with density functional theory to build system-adapted correlation energy functionals. A simple approximation for the unknown effective electron–electron interaction that enters in this combined approach is described, and results for the He series and for the uniform electron gas are briefly reviewed.

Acknowledgments

The authors thank C. Umrigar for the wavefunctions of reference 28. This research was supported by a Marie Curie Intra-European Fellowships within the 6th European Community Framework Programme (contract No. MEIF-CT-2003-500026).