SYMMETRIZED PARTIAL-WAVE METHOD FOR DENSITY-FUNCTIONAL CLUSTER CALCULATIONS

The computational advantage and accuracy of the Harris method is linke d to the simplicity and adequacy of the reference-density model. In an earlier paper, we investigated one way the Harris functional could be extended to systems outside the limits of weakly interacting atoms by making the charge density of the interacting atoms self-consistent wi thin the constraints of overlapping spherical atomic densities. In the present study, a method is presented for augmenting the interacting a tom charge densities with symmetrized pallial-wave expansions on each atomic site. The added variational freedom of the partial waves leads to a scheme capable of giving exact results within a given exchange-co rrelation approximation while maintaining many of the desirable conver gence and stability properties of the original Harris method. Incorpor ation of the symmetry of the cluster in the partial-wave construction further reduces the level of computational effort. This partial-wave c luster method is illustrated by its application to the dimer C-2, the hypothetical atomic cluster Fe6Al8, and the benzene molecule.