ISSN:
1572-8927
Keywords:
Dielectric constant
;
free energy
;
hydration shell
;
ion hydration
;
ion-ion interaction
;
ion-water interaction
;
model for hydration
;
pairing of ions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A hydration-shell model has been developed for calculating the interaction energy between ions in water. The hydration shell around each ion contains a few tightly bound water molecules and a larger number of less tightly bound molecules. The energies of their interaction with the ion and the size of the hydration shell have been derived from published experimental data for ion-water clusters in the gas phase. An expression derived for the interaction energy of two univalent ions in water incorporates the following effects: a Lennard-Jones 6–12 interaction, a Coulomb interaction between the charges, the polarization of the hydration shells by a neighboring ion, and an energy term for the removal of water from the hydration shells when the hydration shells of two ions overlap. The ‘effective’ dielectric constant at small ion-ion distances is the only adjustable parameter. Computed interaction energies for aqueous solutions of twelve alkali halides match experimental values, derived from conductimetric measurements, with an average error of ±14%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00644748
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