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arXiv · 1604.03929

Wave-function inspired density functional applied to the H$_2$/H$_2^+$ challenge

Igor Ying Zhang·Patrick Rinke·Matthias Scheffler
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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 orrelations. We demonstrate that BGE2 is size consistent and one-electron "self-correlation" free. The electron-pair correlation coupling ensures the correct H$_2$ 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 H$_2$ and H$_2^+$ dissociation, which is regarded as a great challenge in density functional theory (DFT). We illustrate the behavior of BGE2 analytically by considering H$_2$ 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.

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Igor Ying Zhang, Patrick Rinke, Matthias Scheffler. 2016-04-13. Wave-function inspired density functional applied to the H$_2$/H$_2^+$ challenge. https://doi.org/10.1088/1367-2630%2F18%2F7%2F073026

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