Study of Separated Electron Pairs in the LiH Molecule

Abstract

The separated-pair model is applied to the ground state of the LiH molecule in an effort to estimate the inherent accuracy of this model, and to investigate a method for computing accurate pair functions. The procedure employs direct calculation with natural orbitals and is found to be rapidly convergent if molecular orbitals are used as first guess in the iteration. The energy for seven σ orbitals is only slightly higher than the corresponding 41-term MO—CI function. A detailed comparison of the two functions is given.