Wachter, Wolfgang and Kunz, Werner and Buchner, Richard and Hefter, Glenn (2005) Is there an anionic Hofmeister effect on water dynamics? Dielectric spectroscopy of aqueous solutions of NaBr, NaI, NaNO3, NaClO4, and NaSCN. JOURNAL OF PHYSICAL CHEMISTRY A, 109 (39). pp. 8675-8683. ISSN 1089-5639,
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A systematic study of the dielectric relaxation spectra of aqueous solutions of NaBr, NaI, NaNO3, NaClO4, and NaSCN has been made over a wide range of frequencies (0.2 <= v/GHz <= 89) and solute concentrations (0.05 <= c/M <= 1.5) at 25 degrees C. The spectra could be adequately described by a single Cole-Cole (CC) process, symmetrically broadened relative to that of pure water. However, similar quality fits were also obtained with a three-Debye-process (3D) model consisting of a small ion-pair contribution at lower frequencies and two solvent relaxations at higher frequencies. Assuming the ions to be solvent separated, the 3D model provided estimates of their association constants and their rate constants for formation and dissociation. The bulk water relaxation times obtained from both models showed almost no dependence on the nature of the anion. Nevertheless, there were subtle differences in the concentration dependences of the relaxation times which correlated with some, but not all, of the anion properties that are believed to be relevant for explaining the anionic Hofmeister series.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | 25 DEGREES C; VISCOSITY B-COEFFICIENTS; ELECTROLYTE-SOLUTIONS; TEMPERATURE-DEPENDENCE; SOLVENT STRUCTURE; HALIDE SOLUTIONS; SODIUM-BROMIDE; IONIC-RADII; RELAXATION; HYDRATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Werner Kunz Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > PD Dr. Richard Buchner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 26 Apr 2021 06:50 |
| Last Modified: | 26 Apr 2021 06:50 |
| URI: | https://pred.uni-regensburg.de/id/eprint/35535 |
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