A resonating broken symmetry configuration interaction approach for double-exchange magnetic systems.

ABSTRACT

The correct description for ion-radical systems has recently attracted much attention from density functional theory (DFT) researchers. Although several hybridization schemes using exact (Hartree-Fock) exchange and DFT exchange-correlation functionals have been proposed, it has been reported that such treatments do not work for the description of ion-radical systems. In this study we show that combining the exact exchange term in the Kohn-Sham DFT (or the Hartree-Fock equation) with the following resonating configuration interaction method is effective for the description of double-exchange type molecular magnetic interactions. The results are analyzed in relation to the 'many-electron self-interaction' concept that was recently proposed by DFT researchers.