Communication: A density functional with accurate fractional-charge and fractional-spin behaviour for s-electrons

Abstract

We develop a new density-functional approach combining physical insight from chemical structure with treatment of multi-reference character by real-space modeling of the exchange-correlation hole. We are able to recover, for the first time, correct fractional-charge and fractional-spin behaviour for atoms of groups 1 and 2. Based on Beckes non-dynamical correlation functional [A. D. Becke, J. Chem. Phys. 119, 2972 (2003)]10.1063/1.1589733 and explicitly accounting for core-valence separation and pairing effects, this method is able to accurately describe dissociation and strong correlation in s-shell many-electron systems. © 2011 American Institute of Physics.