Formulation and numerical approach to molecular systems by the Green function method without Born–Oppenheimer approximation II: Nucleus–electron correlation



We present a nucleus–electron gas model to estimate the nucleus–electron correlation energy. The expression of the effective interaction between nucleus and electron in the framework of the random-phase approximation is derived. We find that the attractive interaction between nucleus and electron can be shielded. The expression of the perturbation energy within the ladder approximation is also derived by some simplicities. We present a numerical procedure to calculate the correlation energy and the correlation potential between nucleus and electron and estimate the nucleus–electron correlation potential. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004