Incorrect Dissociation Behavior of Radical Ions in Density Functional Calculations

Abstract

The current lineup of popular density functional theories, in particular those based on Becke's exchange functionals, fail to predict a correct dissociation behavior in radical ions where charge and spin must be separated (model: H2•+) or where both must be localized on one fragment (model: He2•+). The repercussions of this on the location of certain transition states on radical ion potential energy surfaces are pointed out.