Balance between physical interpretability and energetic predictability in widely used dispersion-corrected density functionals

17 August 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We assess the performance of different dispersion models for several popular density functionals across a diverse set of non-covalent systems, ranging from the benzene dimer to molecular crystals. By analyzing the interaction energies and their individual components, we demonstrate that there exists variability across different systems for empirical dispersion models, which are calibrated for reproducing the interaction energies of specific systems. Thus, parameter fitting may undermine the underlying physics, as dispersion models rely on error compensation among the different components of the interaction energy. Energy decomposition analyses reveal that, the accuracy of revPBE-D3 for some aqueous systems originates from significant compensation between dispersion and charge transfer energies. However, revPBE-D3 is less accurate in describing systems where error compensation is incomplete, such as the benzene dimer. Such cases highlight the propensity for unpredictable behavior in various dispersion-corrected density functionals across a wide range of molecular systems, akin to the behavior of force fields. On the other hand, we find that SCAN-rVV10, a targeted-dispersion approach, affords significant reductions in errors associated with the lattice energies of molecular crystals, whilst it has limited accuracy in reproducing structural properties. Given the ubiquitous nature of non-covalent interactions and the key role of density functional theory in computational sciences, the future development of dispersion models should prioritize the faithful description of the dispersion energy, a shift that promises greater accuracy in capturing the underlying physics across diverse molecular and extended systems.


density functional theory
self-interaction error
delocalization error
generalized gradient approximation
hybrid functionals
molecular interactions
charge transfer
dispersion energy

Supplementary materials

Supporting Information
Additional analyses of interaction energies and associated physical components.


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