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DOE OSTI · 2516757

Evaluation of Density-Functional Tight-Binding Methods for Simulation of Protic Molecular Ion Pairs

Walker, Tyler [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000270233702)·Vuong, Van‐Quan [Boston Univ., MA (United States)] (ORCID:0000000185808532)·Irle, Stephan [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000349954991)·Ma, Jihong [Univ. of Vermont, Burlington, VT (United States)] (ORCID:0000000191428528)
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Abstract

In this work, we benchmark the accuracy of the density-functional tight-binding (DFTB) method, namely the long-range corrected second-order (LC-DFTB2) and third-order (DFTB3) models, for predicting energetics of imidazolium-based ionic liquid (IL) ion pairs. We compare the DFTB models against popular density functionals such as LC-ωPBE and B3LYP, using ab initio domain-based local pair-natural orbital coupled cluster (DLPNO-CC) energies as reference. Calculations were carried out in the gas phase, as well as in aqueous solution using implicit solvent methods. We find that the LC-DFTB2 model shows excellent performance in the gas phase and agrees well with reference energies in implicit solvent, often outperforming DFTB3 predictions for complexation energetics. Our study identifies a range of opportunities for use of the LC-DFTB method and quantifies its sensitivity to protonation states and the types of chemical interactions between ion pairs.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYbenchmarksdensity-functional tight-binding methodsion pairsionization potentialsproton transfer

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Walker, Tyler [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000270233702), Vuong, Van‐Quan [Boston Univ., MA (United States)] (ORCID:0000000185808532), Irle, Stephan [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000349954991), Ma, Jihong [Univ. of Vermont, Burlington, VT (United States)] (ORCID:0000000191428528). 2025-02-13. Evaluation of Density-Functional Tight-Binding Methods for Simulation of Protic Molecular Ion Pairs. https://doi.org/10.1002/jcc.70064

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