Semiclassical electron correlation operator

Abstract

The concept of the correlation operator, introduced 10 years ago as a possible method to model the electron correlation effects with single determinant wave functions [Rassolov, J. Chem. Phys. 110, 3672 (1999)], is revisited. We derive a semiclassical limit of the correlation operator in weakly correlated systems and give its coordinate space representation. Application of this operator to the atomic systems, such as computations of energies of the neutral atoms, energies of the cations, and spin states energy gaps, demonstrates capabilities and limitations of this concept.