OPTIMIZED AND TRANSFERABLE DENSITIES FROM 1ST-PRINCIPLES LOCAL DENSITY CALCULATIONS

From ab initio pseudopotential calculations of the solid we extract atomic-like electron densities which, when overlapped in the crystal, reproduce the self-consistent density except for those components for which the structure factor is zero. We demonstrate the universality of the optimized densities for different crystal structures at varying volumes. These densities are the optimized choice for the Harris functional, and we compare our results with the Finnis contraction of the free atom density and with the effective medium theory ansatz of embedding an atom in a homogenous electron gas.