A mean-field self-interaction correction in density functional theory: implementation and validation for molecules

The implementation and the validation of a simple, self-consistent method to correct the self-interaction error in density functional theory approaches is presented. This model is based on an average density self-interaction correction. The main advantage of the method rests on its simplicity and favorable scaling with the size of the system. We have tested this method on one of the classical pathological problem for density functional theory: the direct estimation of the ionization potential from orbital eigenvalues. The proposed method provides good values for delocalized molecular systems, while large deviations, are obtained for atomic or strongly localized molecular systems.