Exact exchange-correlation potential of effectively interacting Kohn-Sham systems

Physical Review A 101, 012510 (2020)

Exact exchange-correlation potential of effectively interacting Kohn-Sham systems

Shunsuke A. Sato, Angel Rubio

Aiming to combine density functional theory (DFT) and wave-function theory, we study a mapping from the many-body interacting system to an effectively interacting Kohn-Sham system instead of a noninteracting Kohn-Sham system. Because a ground state of effectively interacting systems requires having a solution for the correlated many-body wave functions, this provides a natural framework to many-body wave-function theories such as the configuration interaction and the coupled-cluster method in the formal theoretical framework of DFT. Employing simple one-dimensional two-electron systems—namely, the one-dimensional helium atom, the hydrogen molecule, and the heteronuclear diatomic molecule—we investigate properties of many-body wave functions and exact exchange-correlation potentials of effectively interacting Kohn-Sham systems. As a result, we find that the asymptotic behavior of the exact exchange-correlation potential can be controlled by optimizing that of the effective interaction. Furthermore, the typical features of the exact noninteracting Kohn-Sham system, namely, a spiky feature and a step feature in the exchange-correlation potential for the molecular dissociation limit, can be suppressed by a proper choice of the effective interaction. These findings open a possibility to construct numerically robust and efficient exchange-correlation potentials and functionals based on the effectively interacting Kohn-Sham scheme.

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This work was supported by the European Research Council (Grant No. ERC-2015-AdG694097), the Cluster of Excellence “Advanced Imaging of Matter” (AIM),and JST-CREST under Grant No. JP-MJCR16N5. Support by the Flatiron Institute, a division of the Simons Foundation, is acknowledged. S.A.S. gratefully acknowledges a fellowship from the Alexander von Humboldt Foundation.

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