Assessing UFF and DFT-Tuned Force Fields for Predicting Experimental Isotherms of MOFs
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Cho_JCIM_2025.pdf
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Accepted version
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Author(s)
Cho, Yeongsu
Teetz, Jakob
Kulik, Heather J
Date Issued
March 18, 2025
Journal
Journal of Chemical Information and Modeling
Publisher
American Chemical Society
Citation
Cho, Yeongsu, Teetz, Jakob and Kulik, Heather J. 2025. "Assessing UFF and DFT-Tuned Force Fields for Predicting Experimental Isotherms of MOFs." Journal of Chemical Information and Modeling, 65 (7).
Version
Author's final manuscript
Abstract
Metal-organic frameworks (MOFs) are promising materials for gas storage and
separation applications due to their high tunability and porosity. The rational design of MOFs relies
on accurate computational modeling, with grand canonical Monte Carlo (GCMC) simulations
frequently employed to model gas uptake. However, GCMC predictions often deviate from
experimental observations, limiting their utility in MOF screening. These discrepancies primarily
arise from three factors: inaccuracies in the force field, neglect of atomic motions, and neglect of
structural imperfections in MOFs. In this study, we systematically evaluate the impact of the first
factor on the predictive accuracy of GCMC simulations. We evaluate the widely used Universal
Force Field (UFF) by comparing its predictions with experimental isotherms for four
representative adsorbates, H2, CO2, C2H4, and C2H6, across 379 isotherms from 142 MOFs. The
results show that UFF consistently overestimates gas uptake in GCMC simulations. To isolate the
contribution of force field inaccuracies to errors in GCMC, we develop a practical scheme for
fitting force field parameters to DFT-calculated energies for a large set of MOFs. While the refined
force field improves the accuracy of interatomic interaction energies, its reduction of repulsion,
combined with UFF’s tendency to overestimate gas uptake, ultimately amplifies the overestimation.
Our analysis suggests that improving agreement of gas adsorption prediction with experiments
requires addressing atomic motion and structural defects in MOFs alongside force field
refinements.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
10.1021/acs.jcim.4c02044
