Consistent Density Functional Theory-Based Description of Ion Hydration Through Density-Corrected Many-Body Representations

02 November 2023, Version 3
This content is a preprint and has not undergone peer review at the time of posting.


Delocalization error constrains the accuracy of density functional theory (DFT) in describing molecular interactions in ion–water systems. Using Na+ and Cl− in water as model systems, we calculate the effects of delocalization error in the SCAN functional for describing ion–water and water–water interactions in hydrated ions, and demonstrate that density-corrected SCAN (DC-SCAN) predicts n-body and interaction energies with an accuracy approaching coupled cluster theory. The performance of DC-SCAN is size-consistent, maintaining an accurate description of molecular in- teractions well beyond the first solvation shell. Molecular dynamics simulations at ambient conditions with MB-SCAN(DC) potentials, derived from the many-body expansion, predict the solvation structure of Na+ and Cl− in quantitative agreement with reference data, while simultaneously reproducing the structure of liquid water. Beyond rationalizing the accuracy of density-corrected models of ion hydration, our findings suggest that our unified density-corrected many-body formalism holds great promise for efficient DFT-based simulations of condensed-phase systems with chemical accuracy.


Density functional theory
delocalization error
self-interaction error
ion hydration
molecular interactions
many-body interactions
quantum chemistry
electronic structure
molecular dynamics
statistical mechanics

Supplementary materials

Supplementary Material
Methods. Additional analyses and figures.


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