Work

Atomic forces from correlation energy functionals based on the adiabatic-connection fluctuation-dissipation theorem

Year: 2026

Type: article

Abstract: We extend the capabilities of correlation energy functionals based on the adiabatic-connection fluctuation-dissipation theorem by implementing the analytical atomic forces within the random phase approximation (RPA), in the context of plane waves and pseudopotentials. Forces are calculated at self-consistency through the optimized effective potential method and the Hellmann-Feynman theorem. In addition, non-self-consistent RPA forces, starting from the PBE generalized gradient approximation, are evaluated using density functional perturbation theory. In both cases, we find forces of excellent numerical quality. Furthermore, for most molecules and solids studied, self-consistency is found to have a negligible impact on the computed geometries and vibrational frequencies. The RPA is shown to systematically improve over PBE and, by including the exact-exchange kernel within RPA + exchange (RPAx), through finite-difference total energy calculations, we obtain an accuracy comparable to advanced wavefunction methods. Finally, we estimate the anharmonic shift and provide accurate theoretical references based on RPA and RPAx for the zone-center optical phonon of diamond, silicon, and germanium.

Source: Physical review. B./Physical review. B

DOI: 10.1103/gbcd-74y7

Authors: Damian Contant, Maria Hellgren

Institutions: Centre National de la Recherche Scientifique, Sorbonne Université, Muséum national d'Histoire naturelle, Institut de minéralogie, de physique des matériaux et de cosmochimie, Structure et Instabilité des Génomes

Language: English

Topic: Advanced Chemical Physics Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Centre Informatique National de l’Enseignement Supérieur, Grand Équipement National De Calcul Intensif

Award: G841861718