Bostroem, M. and Ninham, B. W. (2004) Contributions from dispersion and born self-free energies to the solvation energies of salt solutions. JOURNAL OF PHYSICAL CHEMISTRY B, 108 (33). pp. 12593-12595. ISSN 1520-6106,
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That the Born theory provides an accurate means of calculating solvation energies of ions in water has been demonstrated by Rashin and Honig (Rashin, A. A.; Honig, B. J. Phys. Chem. 1985, 89, 5588). They could fit the experimental solvation energies of a number of salts nicely by a simple increase of 7% in the expected radii of all ions. However, as we demonstrate herein, there is an important previously ignored contribution due to the ionic dispersion self-free energy. The ionic parameters necessary to estimate the different contributions to solvation energy are the ionic radii, the ionic polarizabilities, and the ionization potentials. Whereas the polarizabilities and ionization potentials of a number of salts have recently been derived ab initio (in both vacuum and water), the appropriate choices of radii are less well-known. We pursue two different approaches to assign the ionic radii. In the first approach, we find that an increase of all expected radii by 23% gives reasonable agreement between theory and experiment (to within 6%). In the second approach, we increased the expected radii of six ions separately (10-30%) to obtain a best fit for the nine salts investigated. In this second approach, the deviations between theory and experiment were less than 0.1%. The essential point is that a proper theory must include contributions from both electrostatic (Born) and electrodynamic (dispersion) self-free energies.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ION-BINDING; INTERFACE; WATER; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 02 Jul 2021 08:17 |
| Last Modified: | 02 Jul 2021 08:17 |
| URI: | https://pred.uni-regensburg.de/id/eprint/37326 |
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