Self-Interaction-Corrected Random Phase Approximation.

Area of Science:

• Quantum chemistry
• Computational physics
• Materials science

Background:

• The random phase approximation (RPA) often overestimates short-range correlation energy, requiring corrections.
• Existing beyond-RPA methods show inconsistent performance for thermodynamic and dissociation properties.
• RPA+ improves total energies but not atomization energies for molecules, similar to RPA.

Purpose of the Study:

• To investigate the transferability of generalized RPA+ (gRPA+) improvements to molecular atomization energies, ionization energies, and electron affinities.
• To assess the applicability of beyond-RPA corrections based on density functional approximations.
• To adapt gRPA+ for localized basis set codes using a modified approach (mgRPA+).

Main Methods:

• Implementation of a modified generalized RPA+ (mgRPA+) method.
• Application of mgRPA+ to calculate atomization energies, ionization energies, and electron affinities of molecules.
• Comparison of mgRPA+ results with RPA and RPA+.

Main Results:

• The modified gRPA+ (mgRPA+) method shows significant improvements for molecular atomization energies, ionization energies, and electron affinities compared to RPA and RPA+.
• mgRPA+ demonstrates enhanced accuracy for systems calculated with localized basis functions.
• The study validates the potential of gRPA+-based corrections for improving molecular properties.

Conclusions:

• Beyond-RPA corrections based on density functional approximations, like mgRPA+, offer a promising avenue for accurate molecular property predictions.
• The mgRPA+ method provides a computationally feasible way to improve upon RPA and RPA+ for molecular calculations.
• Further investigation into these beyond-RPA methods is warranted for broader applicability in quantum chemistry and materials science.