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

Area of Science:

• Quantum chemistry
• Computational materials science

Background:

• Density-corrected Hartree-Fock density functional theory (DC(HF)-DFT) and its extension, C(HF)-DFT, offer efficient computational methods.
• The random phase approximation (RPA) is a powerful tool for electronic structure calculations.

Purpose of the Study:

• To develop and evaluate a new computational methodology, corrected Hartree-Fock RPA (C(HF)-RPA).
• To combine C(HF)-DFT with RPA, incorporating an orbital energy correction.

Main Methods:

• Implementation of C(HF)-RPA by augmenting C(HF)-DFT with RPA.
• Evaluation across various RPA variants: direct RPA (dRPA), RPA with approximate exchange, and RPA with second-order screened exchange.

Main Results:

• The C(HF)-dRPA method shows very promising performance.
• RPA methods incorporating exchange kernels often exhibit over-corrections when combined with C(HF)-DFT.

Conclusions:

• C(HF)-RPA presents a viable advancement in quantum chemical calculations.
• Careful consideration of exchange components is necessary when using C(HF)-RPA with exchange-inclusive RPA methods.