Converged Hartree-Fock and electron correlation calculations using systematically constructed basis sets of primitive Gaussian type functions of s-symmetry

The convergence of the matrix Hartree-Fock energies of Li+, H- and LiH prototype systems and electron correlation energies of LiH are studied when a systematic procedure for the construction of even-tempered basis sets of primitive Gaussian type functions of s-symmetry is employed. It is shown that an accuracy approaching the sub-mu Hartree level can be achieved for the total energies of Li+, H- and LiH within the Hartree-Fock approximation. While an accuracy approaching the sub-mu Hartree level can be achieved for the total energy of LiH within the Moller-Plesset perturbation level, an accuracy approaching the mu Hartree level can be achieved within the configuration interaction level. The Hartree-Fock energies of LiH approach the saturation faster than do the electron correlation energies. The convergence of Moller-Plesset perturbation series was basis set size dependent, but the convergence rate and the related Pople approximation were basis set size independent.