Gaussian charge-transfer charge distributions for non-self-consistent electronic structure calculations

We present a scheme to construct charge densities for non-self-consistent density functional theory calculations. Effects of charge transfer are added onto the density of overlapping atomic charge densities by means of charge-neutral spherical atom-centered Gaussian charge distributions that have been fitted to the self-consistent charge density in amorphous model systems. The electronic structure and forces obtained from non-self-consistent calculations using these a priori constructed charge densities are in good agreement with fully self-consistent calculations, and the Gaussian charge-transfer charges exhibit a satisfactory transferability between compounds of similar stochiometry but different geometry.