2009/10/21 by Michael Seidl, Paola Gori-Giorgi · 1 citation
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1103/physreva.81.012508
published as Phys. Rev. A 81, 012508 (2010) · 9 pages, submitted to PRA
arxiv created 2009/10/21 · arxiv updated 2015/05/14
The adiabatic connection of density functional theory (DFT) for electronic systems is generalized here to negative values of the coupling strength α (with \em attractive electrons). In the extreme limit α→-∞ a simple physical solution is presented and its implications for DFT (as well as its limitations) are discussed. For two-electron systems (a case in which the present solution can be calculated exactly), we find that an interpolation between the limit α→-∞ and the opposite limit of infinitely strong repulsion (α→+∞) yields a rather accurate estimate of the second-order correlation energy E\cor\glt[ρ] for several different densities ρ, without using virtual orbitals. The same procedure is also applied to the Be isoelectronic series, analyzing the effects of near-degeneracy.