Water molecule by the self-consistent atomic deformation method

Abstract

We present a density functional method which expresses the charge density of a system of atoms as a sum over localized atomiclike densities derived from potentials defined variationally from the total energy expression, which includes contributions from overlapping densities. An approach for systematically increasing the variational freedom of the atomiclike densities is introduced and tested for the water molecule. For the water molecule our method results in complete charge transfer for sufficiently small bond lengths and reverses the charge transfer at large bond lengths. In case of complete charge transfer the overlap contributions are zero, allowing a direct comparison with the traditional Kohn--Sham approach.