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DOE OSTI · 3017907

Long-Range Fit: A Software Package for the Representation and Study of Long-Range Molecular Interactions

Batista-Planas, Adrian L. [Missouri Univ. of Science and Technology, Rolla, MO (United States)]·Quintas-Sánchez, Ernesto [Missouri Univ. of Science and Technology, Rolla, MO (United States)] (ORCID:0000000243788745)·Dawes, Richard [Missouri Univ. of Science and Technology, Rolla, MO (United States)] (ORCID:0000000224934671)
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Abstract

Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions─with electrostatic, induction, and dispersion as the main components─play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via a multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed long-range-fit (LRF), an interactive and user-friendly software package designed to automate the generation and fitting of long-range interaction terms for arbitrary molecules in nondegenerate (ground or excited) electronic states. We have derived and implemented all terms up to 15th order, without approximations, via a spherical tensor representation, with symmetry adaptation to all molecular point-group symmetries. The resulting potential energy surface is compatible with most representations of the close interaction region.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY74 ATOMIC AND MOLECULAR PHYSICSelectrostaticsgroup theorymolecular interactionsmolecules potential energy

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Batista-Planas, Adrian L. [Missouri Univ. of Science and Technology, Rolla, MO (United States)], Quintas-Sánchez, Ernesto [Missouri Univ. of Science and Technology, Rolla, MO (United States)] (ORCID:0000000243788745), Dawes, Richard [Missouri Univ. of Science and Technology, Rolla, MO (United States)] (ORCID:0000000224934671). 2026-01-27. Long-Range Fit: A Software Package for the Representation and Study of Long-Range Molecular Interactions. https://doi.org/10.1021/acs.jctc.5c01984

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