Kohn–Sham energy decomposition for molecules in a magnetic field

Reimann, Sarah and Borgoo, Alex and Austad, Jon and Tellgren, Erik I. and Teale, Andrew M. and Helgaker, Trygve and Stopkowicz, Stella (2019) Kohn–Sham energy decomposition for molecules in a magnetic field. Molecular Physics, 117 (1). pp. 97-109. ISSN 1362-3028

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Abstract

We study the total molecular electronic energy and its Kohn–Sham components within the framework of magnetic-field density-functional theory (BDFT), an alternative to current-dependent density-functional theory (CDFT) for molecules in the presence of magnetic fields. For a selection of closed-shell dia- and paramagnetic molecules, we investigate the dependence of the total electronic energy and its Kohn–Sham components on the magnetic field. Results obtained from commonly used density-functional approximations are compared with those obtained from Lieb optimizations based on magnetic-field dependent relaxed coupled-cluster singles-and-doubles (CCSD) and second-order Møller–Plesset (MP2) densities. We show that popular approximate exchange–correlation functionals at the generalized-gradient-approximation (GGA), meta-GGA, and hybrid levels of theory provide a good qualitative description of the electronic energy and its Kohn–Sham components in a magnetic field—in particular, for the diamagnetic molecules. The performance of Hartree–Fock theory, MP2 theory, CCSD theory and BDFT with different exchange–correlation functionals is compared with coupled-cluster singles-doubles-perturbative-triples (CCSD(T)) theory for the perpendicular component of the magnetizability. Generalizations of the TPSS meta-GGA functional to systems in a magnetic field work well—the cTPSS functional, in particular, with a current-corrected kinetic-energy density, performs excellently, providing an accurate and balanced treatment of dia- and paramagnetic systems and outperforming MP2 theory.

Item Type: Article
Keywords: electron correlation, density-functional theory, current density-functional theory, magnetic-field density-functional theory, coupled-cluster theory, molecular magnetic properties, strong magnetic fields
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Chemistry
Identification Number: https://doi.org/10.1080/00268976.2018.1495849
Depositing User: Teale, Andrew
Date Deposited: 04 Jul 2018 08:07
Last Modified: 01 Apr 2019 10:18
URI: http://eprints.nottingham.ac.uk/id/eprint/52748

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