Screening Effects on the Electronic Structure of Atoms and Molecules

Abstract

The variational self consistent field molecular orbital method is used to compute both atomic and molecular energies for the Yukawa potential. Both, closed-shell and openshell Slater determinant type of configuration wave functions are expanded as linear combinations of Gaussian basis functions, for which a complete analytical solution for all the required basic integrals is obtained. The energies obtained by this method for the hydrogen atom compare satisfactorilly with more accurate calculations, even for short expansions of the orbitals. For the groung states of the H+2 and H2 molecules our model predicts that the bond length increases and the dissociation decreases as the screening parameter increases.