SYSTEMATIC TREATMENT OF CORRELATIONS IN A GENERALIZED HARTREE-FOCK APPROXIMATION

The HartreeFock (HF) approximation is generalized to the study of n-pa rticle states, taking correlation effects in interacting quantum-mecha nical many-particle systems systematically into account. The case of n = 2 is developed explicitly. It is shown that the form of the HF equa tions remains essentially the same as in the usual formulation, but wi th appropriate interpretations of various parameters in terms of n-par ticle, rather than single; particle, states. We show results of calcul ations for model systems that illustrate the power of the method when compared to ordinary versions of the HF treatment.