title: Orbital currents in the Colle-Salvetti correlation energy functional and the degeneracy problem.
abstract: Popular density functionals for the exchange-correlation energy typically fail to reproduce the degeneracy of different ground states of open-shell atoms. As a remedy, functionals which explicitly depend on the current density have been suggested. We present an analysis of this problem by investigating functionals that explicitly depend on the Kohn-Sham orbitals. Going beyond the exact-exchange approximation by adding correlation in the form of the Colle-Salvetti functional, we show how current-dependent terms enter the Colle-Salvetti expression and their relevance is evaluated. A very good description of the degeneracy of ground states for atoms of the first and second rows of the Periodic Table is obtained.
authors: Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
authors: S
authors: S
authors: Pittalis
authors: S
authors: S
authors: Kurth
authors: S
authors: S
authors: Sharma
authors: E K U
authors: EK
authors: Gross