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arXiv · 2608.14147

Accurate and efficient calculation of atomic forces in solids with non-self-consistent hybrid functionals

Damian Contant·Maria Hellgren
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Abstract

Hybrid functionals are routinely employed self-consistently within the generalized Kohn-Sham framework. The evaluation of the nonlocal Fock exchange operator makes hybrid functional calculations computationally expensive, in particular with plane-wave basis sets. Here, we investigate the advantages of non-self-consistent hybrid functional calculations, focusing on the evaluation of atomic forces. The analytical force terms that arise due to non-self-consistency are computed using density functional perturbation theory (DFPT), as implemented within the Quantum ESPRESSO distribution. A non-self-consistent hybrid force calculation thus consists of self-consistent DFPT calculations with a local or semi-local functional and a single evaluation of the Fock exchange operator. The overall computational cost is, thereby, reduced in general, especially for solids that require a dense Brillouin-zone sampling. Moreover, results for structural parameters are barely affected by self-consistency, and vibrational frequencies are typically agreeing within 0.5%, thus making non-self-consistent calculations an interesting alternative.

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Damian Contant, Maria Hellgren. 2026-08-14. Accurate and efficient calculation of atomic forces in solids with non-self-consistent hybrid functionals. https://arxiv.org/abs/2608.14147

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