BINDING-PROPERTIES OF 3D TRANSITION-METALS IN A GENERALIZED DENSITY-FUNCTIONAL THEORY

In a preceding paper we have reported on band-gap corrections in semic onductors and insulators that were calculated within a generalized den sity-functional (GDF) theory. Similar to an earlier idea of Gunnarsson and Jones, we describe exchange and correlation effects by suitably m odeled pair-correlation factors. They are subject to certain sum rules that ensure the absence of self-interaction in the electron-electron interaction integrals. The resulting exchange-correlation potential in the GDF-derived one-particle equations is ''nonlocal'' (NL), as disti nct from its local-density approximation (LDA) analogue, which has so far almost exclusively been used in performing DF calculations on soli ds. The present work is concerned with the extension of our previous N L calculations on free atoms and nonmetals to 3d transition metals. It turns out that the general trends in the binding properties of these metals (cohesive energies, equilibrium lattice parameters, bulk moduli ) are not changed by replacing the LDA expressions with their NL analo gues. However, in using the latter expressions, one achieves a sizable reduction of the ''overbinding effect,'' which confirms the long-stan ding suspicion of being LDA related.