Abstract
The adiabatic connection of density functional theory (DFT) for electronic systems is generalized here to negative values of the coupling strength α (with 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 EcGL2[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. © 2010 The American Physical Society.
Original language | English |
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Article number | 012508 |
Pages (from-to) | 012508 |
Number of pages | 9 |
Journal | Physical Review A. Atomic, Molecular and Optical Physics |
Volume | 81 |
DOIs | |
Publication status | Published - 2010 |