Comparison of Density-Matrix Corrections to Density Functional Theory

TL;DR

This paper compares various density-matrix correction methods to standard DFT and Hartree-Fock, analyzing their dependence on functional choice and benchmarking their performance on selected systems.

Contribution

It introduces a generalized iDMFT approach with density functionals and compares it to existing 1-RDMFT methods across different functionals and systems.

Findings

1-RDMFT improves DFT for static correlation.

Generalized iDMFT incorporates density functionals.

Benchmark results show varying accuracy depending on the functional.

Abstract

Density functional theory (DFT), one of the most widely utilized methods available to computational chemistry, fails to describe systems with statically correlated electrons. To address this shortcoming, in previous work we transformed DFT into a one-electron reduced density matrix theory (1-RDMFT) via the inclusion of a quadratic one-electron reduced density matrix (1-RDM) correction. Here, we combine our 1-RDMFT approach with different DFT functionals as well as Hartree-Fock to elucidate the method's dependence on the underlying functional selection. Furthermore, we generalize the information density matrix functional theory (iDMFT), recently developed as a correction to the Hartree-Fock method, by incorporating density functionals in place of the Hartree-Fock functional. We relate iDMFT mathematically to our approach and benchmark the two with a common set of functionals and systems.