Corrected Density Functional Theory and the Random Phase Approximation: Improved Accuracy at Little Extra Cost

TL;DR

This paper introduces C(HF)-RPA, a combined method of corrected Hartree-Fock DFT and RPA, which improves accuracy in electronic structure calculations with minimal additional computational cost.

Contribution

It develops and evaluates a new combined methodology, C(HF)-RPA, integrating corrected HF DFT with RPA to enhance computational accuracy.

Findings

C(HF)-dRPA shows promising performance.

RPA with exchange methods can over-correct certain problems.

The methodology offers improved accuracy at little extra cost.

Abstract

We recently introduced an efficient methodology to perform density-corrected Hartree-Fock density functional theory (DC(HF)-DFT) calculations and an extension to it we called "corrected" HF DFT (C(HF)-DFT). In this work, we take a further step and combine C(HF)-DFT, augmented with a straightforward orbital energy correction, with the random phase approximation (RPA). We refer to the resulting methodology as corrected HF RPA (C(HF)-RPA). We evaluate the proposed methodology across various RPA methods: direct RPA (dRPA), RPA with an approximate exchange kernel (RPA-AXK), and RPA with second-order screened exchange (RPA-SOSEX). C(HF)-dRPA, in particular, demonstrates very promising performance; for RPA with exchange methods we find over-corrections for certain chemical problems.