Many-Body Effects Determine the Local Hydration Structure of Cs+ in Solution

26 December 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


A systematic analysis of the hydration structure of Cs+ ions in solution is derived from simulations carried out using a series of molecular models built upon a hierarchy of approximate representations of many-body effects in ion-water interactions. It is found that a pairwise-additive model, commonly used in biomolecular simulations, provides poor agreement with experimental X-ray spectra, indicating an incorrect description of the underlying hydration structure. Although the agreement with experiment improves in simulations with a polarizable model, the predicted hydration structure is found to lack the correct sequence of water shells. Progressive inclusion of explicit many- body effects in the representation of Cs+-water interactions as well as account for nuclear quantum effects is shown to be necessary for quantitatively reproducing the experimental spectra. Besides emphasizing the importance of many-body effects, these results suggests that molecular models rigorously derived from many-body expansions hold promise for realistic simulations of aqueous solutions.


hydration properties
many-body interactions
x-ray spectroscopy
water models
molecular dynamics
nuclear quantum effects

Supplementary materials

supp info


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