Abstract
We start from the Bethe-Goldstone equation (BGE) to derive a simple orbital-dependent correlation functional - BGE2 - which terminates the BGE expansion at the second-order, but retains the self-consistent coupling of electron-pair correlations. We demonstrate that BGE2 is size consistent and one-electron 'self-correlation' free. The electron-pair correlation coupling ensures the correct H2 dissociation limit and gives a finite correlation energy for any system even if it has a no energy gap. BGE2 provides a good description of both H2 and dissociation, which is regarded as a great challenge in density functional theory (DFT). We illustrate the behavior of BGE2 analytically by considering H2 in a minimal basis. Our analysis shows that BGE2 captures essential features of the adiabatic connection path that current state-of-the-art DFT approximations do not.
Original language | English |
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Article number | 073026 |
Pages (from-to) | 1-16 |
Journal | New Journal of Physics |
Volume | 18 |
Issue number | 7 |
DOIs | |
Publication status | Published - 1 Jul 2016 |
MoE publication type | A1 Journal article-refereed |
Keywords
- adiabatic-connetion path
- density-functional theory
- molecular dissociation
- near-degeneracy correlation