CONSTRUCTION OF TRANSFERABLE SPHERICALLY AVERAGED ELECTRON POTENTIALS

A new scheme for constructing approximate effective electron potential s within density-functional theory is proposed. The scheme consists of calculating the effective potential for a series of reference systems , and then using these potentials to construct the potential of a gene ral system. To make contact with the reference system the neutral-sphe re radius of each atom is used. The scheme can simplify calculations w ith partial wave methods in the atomic-sphere or muffin-tin approximat ion, since potential parameters can be precalculated and then for a ge neral system obtained through simple interpolation formulas. We have a pplied the scheme to construct electron potentials of phonons, surface s, and different crystal structures of silicon and aluminium atoms, an d found excellent agreement with the self-consistent effective potenti al. By using an approximate total electron density obtained from a sup erposition of atom-based densities, the energy zero of the correspondi ng effective potential can be found and the energy shifts in the mean potential between inequivalent atoms can therefore be directly estimat ed. This approach is shown to work well for surfaces and phonons of si licon.