Corrected density functional theory and the random phase approximation: Improved accuracy at little extra cost

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] [Graf and Thom, J. Chem. Theory Comput. 19 5427-5438 (2023)]. 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, and RPA with second-order screened exchange. C(HF)-dRPA demonstrates very promising performance; for RPA with exchange methods, on the other hand, we often find over-corrections.

Automated summary

We introduced an efficient methodology, called DC(HF)-DFT, for density-corrected Hartree-Fock density functional theory calculations, and its extension called corrected HF DFT (C(HF)-DFT). In this study, we further combined C(HF)-DFT with the random phase approximation (RPA) and referred to it as corrected HF RPA (C(HF)-RPA). We evaluated the proposed methodology using various RPA methods and found that C(HF)-dRPA showed promising performance, while over-corrections were often observed in RPA with exchange methods.