Charge renormalization at the large-D limit for N-electron atoms and weakly bound systems

We develop a systematic way to determine an effective nuclear charge ZD R such that the Hartree– Fock results will be significantly closer to the exact energies by utilizing the analytically known large-D limit energies. This method yields an expansion for the effective nuclear charge in powers of (1/D), which we have evaluated to the first order. This first order approximation to the desired effective nuclear charge has been applied to two-electron atoms with Z52–20, and weakly bound systems such as H. The errors for the two-electron atoms when compared with exact results were reduced from ;0.2% for Z52 to ;0.002% for large Z . Although usual Hartree–Fock calculations for H show this to be unstable, our results reduce the percent error of the Hartree–Fock energy from 7.6% to 1.86% and predicts the anion to be stable. For N-electron atoms ~N53–18, Z53–28!, using only the zeroth order approximation for the effective charge significantly reduces the error of Hartree–Fock calculations and recovers more than 80% of the correlation energy. © 1995 American Institute of Physics.