On the Accuracy of the Algebraic Approximation in Molecular Electronic Structure Studies: VII. Matrix Valence Bond Calculations for the Hydrogen Molecule Ground State

摘要

The accuracy of generalized valence bond calculations made within the algebraic approx-imation (that is by making finite basis set expansions) is investigated by using systematic sequences of distributed even-tempered Gaussian basis sets for the ground state of the hydrogen molecule. In contrast to the matrix Hartree-Fock model, the valence bond model approach afford a qualitatively correct description of molecular dissociation processes and provides a useful reference with respect to which dynamic electron correlation effects can be described.-A basis set is developed which sup-ports an accuracy approaching the sub-/ihartree level in energy calculations using the matrix valence bond and matrix Hartree-Fock approaches. A comparison is made with the results of second-order many-body perturbation theory calculations. An interpretation of the utility of bond-centred basis functions is provided in terms of generalized valence bond theory.