What DFT method is the most accurate for calculating hydrogen bonding? Dispersion correction seems essential to large-system hydrogen bonds, whereas dispersion correction tends to overestimate hydrogen bonds in small systems. Any suggestions (possibly with references) would be helpful.
Any hybrid DFT functional is adequate to compute the H-bond. As you said, dispersive correction is essentially required in the large molecular system. However, it is useless to compute the small molecular system.
Article Density Functional Theory and Hydrogen Bonds: Are We There Yet?
Nevertheless, i think the post-HF method is the best choice to compute the H-bond energy if the molecular system is not too large.
I have tried a lot of functionals and basis set
The Best DFT method is MN12-L functional and def2_SVP basis set.
https://doi.org/10.1007/s11144-022-02316-5.
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When selecting a density functional for modeling hydrogen bonding, it is important to consider the size of the system being studied, the basis set being used, and the exchange-correlation functional. For small systems, dispersion-corrected double-hybrid functionals such as B2PLYP-D3 Article Comprehensive Benchmarking of a Density-Dependent Dispersion...
and B2GP-PLYP may provide the most accurate results, as they include electron correlation effects not present in traditional density functionals. However, it should be noted that these functionals are most effective for systems with strong hydrogen bonding. For larger systems, a more computationally efficient functional such as SCAN may be more suitable, as it tends to perform well for hydrogen bonding in large systemsArticle SCAN: An Efficient Density Functional Yielding Accurate Stru...
. Whichever approach you choose, it is necessary to benchmark any DFT method and basis set against accurate reference data before using it for your specific application.- Badges
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