Variational Dirac-Coulomb explicitly correlated computations for atoms and molecules

• URL: http://arxiv.org/abs/2110.06638v4
• Date: Tue, 1 Feb 2022 08:21:29 GMT
• Title: Variational Dirac-Coulomb explicitly correlated computations for atoms and molecules
• Authors: P\'eter Jeszenszki, D\'avid Ferenc, Edit M\'atyus
• Abstract summary: Dirac-Coulomb equation with positive-energy projection is solved using explicitly correlated Gaussian functions. The no-pair Dirac-Coulomb energy converged to a parts-per-billion precision is compared with perturbative results for atomic and molecular systems.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The Dirac-Coulomb equation with positive-energy projection is solved using explicitly correlated Gaussian functions. The algorithm and computational procedure aims for a parts-per-billion convergence of the energy to provide a starting point for further comparison and further developments in relation with high-resolution atomic and molecular spectroscopy. Besides a detailed discussion of the implementation of the fundamental spinor structure, permutation and point-group symmetries, various options for the positive-energy projection procedure are presented. The no-pair Dirac-Coulomb energy converged to a parts-per-billion precision is compared with perturbative results for atomic and molecular systems with small nuclear charge numbers. The subsequent paper [Paper II: D. Ferenc, P. Jeszenszki, and E. M\'atyus (2022)] describes the implementation of the Breit interaction in this framework.

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