An Embedded Fragment Method for Molecules in Strong Magnetic Fields

Speake, Benjamin T.; Irons, Tom J. P.; Wibowo, Meilani; Johnson, Andrew G.; David, Grégoire; Teale, Andrew M.

Abstract

An extension of the embedded fragment method for calculations on molecular clusters is presented, which includes strong external magnetic fields. The approach is flexible, allowing for calculations at the Hartree-Fock, current-density-functional theory, Møller-Plesset perturbation theory, and coupled-cluster levels using London atomic orbitals. For systems consisting of discrete molecular subunits, calculations using London atomic orbitals can be performed in a computationally tractable manner for systems beyond the reach of conventional calculations, even those accelerated by resolution-of-the-identity or Cholesky decomposition methods. To assess the applicability of the approach, applications to water clusters are presented, showing how strong magnetic fields enhance binding within the clusters. However, our calculations suggest that, contrary to previous suggestions in the literature, this enhanced binding may not be directly attributable to strengthening of hydrogen bonding. Instead, these results suggest that this arises for larger field strengths as a response of the system to the presence of the external field, which induces a charge density build up between the monomer units. The approach is embarrassingly parallel and its computational tractability is demonstrated for clusters of up to 103 water molecules in triple-ζ basis sets, which would correspond to conventional calculations with more than 12 000 basis functions.

Citation

Speake, B. T., Irons, T. J. P., Wibowo, M., Johnson, A. G., David, G., & Teale, A. M. (2022). An Embedded Fragment Method for Molecules in Strong Magnetic Fields. Journal of Chemical Theory and Computation, 18(12), 7412-7427. https://doi.org/10.1021/acs.jctc.2c00865

• Journal Article Type: Article
• Acceptance Date: Oct 20, 2022
• Online Publication Date: Nov 22, 2022
• Publication Date: Dec 13, 2022
• Deposit Date: Jan 30, 2023
• Publicly Available Date: Jan 31, 2023
• Journal: Journal of Chemical Theory and Computation
• Print ISSN: 1549-9618
• Electronic ISSN: 1549-9626
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 18
• Issue: 12
• Pages: 7412-7427
• DOI: https://doi.org/10.1021/acs.jctc.2c00865
• Keywords: Physical and Theoretical Chemistry; Computer Science Applications
• Public URL: https://nottingham-repository.worktribe.com/output/14040541
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.jctc.2c00865