ON INTRAPAIR AND INTERPAIR ELECTRON CORRELATION IN LIF2

This article presents the intrapair and interpair electron correlation energies of LiF2. The total interpair correlation energy predominates . Hence, in building models for correcting post-Hartree-Fock calculati ons to obtain accurate electron correlation energies, the interpair el ectron correlation energy must be considered. Based on this result and our previous results, a fundamental assumption underlying the so-call ed higher-level correction in the Pople G1 the G2 theory is flawed. (C ) 1997 John Wiley & Sons, Inc.