Improving gas adsorption modeling for MOFs by local calibration of Hubbard U parameters
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154101_1_5.0201934.pdf
Description
Published version
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4.23 MB
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Adobe PDF
Checksum (MD5)
b401fa8fee441b92c4e4be50f3518853
Author(s)
Cho, Yeongsu
Kulik, Heather J
Date Issued
April 16, 2024
Journal
The Journal of Chemical Physics
Publisher
AIP Publishing
Citation
Yeongsu Cho, Heather J. Kulik; Improving gas adsorption modeling for MOFs by local calibration of Hubbard U parameters. J. Chem. Phys. 21 April 2024; 160 (15): 154101.
Version
Final published version
Abstract
While computational screening with density functional theory (DFT) is frequently employed for the screening of metal–organic frameworks (MOFs) for gas separation and storage, commonly applied generalized gradient approximations (GGAs) exhibit self-interaction errors, which hinder the predictions of adsorption energies. We investigate the Hubbard U parameter to augment DFT calculations for full periodic MOFs, targeting a more precise modeling of gas molecule–MOF interactions, specifically for N2, CO2, and O2. We introduce a calibration scheme for the U parameter, which is tailored for each MOF, by leveraging higher-level calculations on the secondary building unit (SBU) of the MOF. When applied to the full periodic MOF, the U parameter calibrated against hybrid HSE06 calculations of SBUs successfully reproduces hybrid-quality calculations of the adsorption energy of the periodic MOF. The mean absolute deviation of adsorption energies reduces from 0.13 eV for a standard GGA treatment to 0.06 eV with the calibrated U, demonstrating the utility of the calibration procedure when applied to the full MOF structure. Furthermore, attempting to use coupled cluster singles and doubles with perturbative triples calculations of isolated SBUs for this calibration procedure shows varying degrees of success in predicting the experimental heat of adsorption. It improves accuracy for N2 adsorption for cases of overbinding, whereas its impact on CO2 is minimal, and ambiguities in spin state assignment hinder consistent improvements of O2 adsorption. Our findings emphasize the limitations of cluster models and advocate the use of full periodic MOF systems with a calibrated U parameter, providing a more comprehensive understanding of gas adsorption in MOFs.
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
https://doi.org/10.1063/5.0201934
