Finding Order in the Disordered Hydration Shell of Rapidly Exchanging Water Molecules around the Heaviest Alkali Cs+ and Fr+
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Here, we report the structural and dynamical characterization of the intrinsically disordered hydration shells of the heaviest alkali ions, Cs+ and Fr+, obtained in ab initio molecular dynamics simulations. The knowledge of solvation and complexation properties of short-lived Fr+ is very limited and mostly based on extrapolations from the smaller alkali metal ions. To this end, we provide a critical insight into Fr+ solvation, demonstrating an extreme example of disordered solvation with no distinction between the ion-bound and solvent-bound states of water based on the ion–water distance. However, these two states are distinguished through distance-solvent rearrangement correlation, where either coordination number or electric field is employed to treat solvent rearrangement. Utilizing reaction rate theory, we find that the water exchange time scale for Fr+ (2.1–2.3 ps) is unexpectedly slower than for Cs+ (0.5–1.2 ps), because Fr+ experiences stronger nonequilibrium solvent effects. This study provides a new perspective on weak and hydrophobic solvation.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1489106
- Journal Information:
- Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Vol. 122, Issue 50; ISSN 1520-6106
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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