Effective local potentials for density and density-matrix functional approximations with non-negative screening density

Pitts, Thomas C.; Bousiadi, Sofia; Gidopoulos, Nikitas I.; Lathiotakis, Nektarios N.

Abstract

A way to improve the accuracy of the spectral properties in density functional theory (DFT) is to impose constraints on the effective, Kohn-Sham (KS), local potential [J. Chem. Phys. 136, 224109 (2012)]. As illustrated, a convenient variational quantity in that approach is the “screening” or “electron repulsion” density, ρrep, corresponding to the local, KS Hartree, exchange and correlation potential through Poisson’s equation. Two constraints, applied to this minimization, largely remove self-interaction errors from the effective potential: (i) ρrep integrates to N −1, where N is the number of electrons, and (ii) ρrep ≥ 0 everywhere. In the present work, we introduce an effective “screening” amplitude, f , as the variational quantity, with the screening density being ρrep = f 2. In this way, the positivity condition for ρrep is automatically satisfied and the minimization problem becomes more efficient and robust. We apply this technique to molecular calculations employing several approximations in DFT and in reduced density matrix functional theory. We find that the proposed development is an accurate, yet robust, variant of the constrained effective potential method.

Citation

Pitts, T. C., Bousiadi, S., Gidopoulos, N. I., & Lathiotakis, N. N. (2023). Effective local potentials for density and density-matrix functional approximations with non-negative screening density. The Journal of Chemical Physics, 158(18), Article 184105. https://doi.org/10.1063/5.0143757

• Journal Article Type: Article
• Acceptance Date: Apr 20, 2023
• Publication Date: May 14, 2023
• Deposit Date: Apr 25, 2023
• Publicly Available Date: Apr 25, 2023
• Journal: The Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 158
• Issue: 18
• Article Number: 184105
• DOI: https://doi.org/10.1063/5.0143757