## Atomic and molecular correlation energies with explicitly correlated Gaussian geminals. III. Coupled cluster treatment for He, Be, H/sub 2/, and LiH

Cizek's coupled-pair, many-electron theory is formulated in a first-quantized, basis set independent way. The resulting set of coupled integro-differential equations for symmetry-adapted spinless pair functions is then solved variationally using the basis set of explicitly correlated Gaussian geminals. In this way, accurate values of the correlation energies in both the linear and quadratic versions of the coupled-pair theory are obtained for He, Be, H/sub 2/, and LiH. These values are expected to be saturated up to within a fraction of 1%. For Be our results are practically identical with the basis set independent coupled-pair energies obtained recently by Lindgren andmore »