The combined effect of cations and anions on the dynamics of water
- 17 February 2012
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 14 (18), 6280-6288
- https://doi.org/10.1039/c2cp23882a
Abstract
We studied the orientational relaxation of the OD-stretch vibration of HDO molecules in concentrated solutions of alkali-halide salts (NaCl, NaI, CsCl and KI) in isotopically diluted water (4% D2O in H2O), using polarization-resolved femtosecond infrared pump–probe spectroscopy (fs-IR). We were able to distinguish the orientational dynamics of the water molecules solvating the halide ions from the dynamics of the bulk water and the water solvating the cations. We found that the reorientation of the halide-bound molecules shows two strongly different components (2.0 ± 0.3 ps and 9 ± 1 ps), related to a wiggling motion of the OD group hydrogen-bonded to the anion, and rotational diffusion of the molecule over the charged anion surface, respectively. The relative amplitudes of the two components are dependent on the nature of both the anion and cation, and on the concentration. These results show that cations can have a profound effect on the solvation shell dynamics of their counter-ions.This publication has 33 references indexed in Scilit:
- Rattling in the Cage: Ions as Probes of Sub-picosecond Water Network DynamicsJournal of the American Chemical Society, 2009
- Vibrational Spectroscopy as a Probe of Structure and Dynamics in Liquid WaterChemical Reviews, 2009
- Water structure, dynamics, and vibrational spectroscopy in sodium bromide solutionsThe Journal of Chemical Physics, 2009
- Effect of Ions on the Structure of Water: Structure Making and BreakingChemical Reviews, 2009
- Getting Specific About Specific Ion EffectsScience, 2008
- Hydration of Sodium, Potassium, and Chloride Ions in Solution and the Concept of Structure Maker/BreakerThe Journal of Physical Chemistry B, 2007
- The Effects of Dissolved Halide Anions on Hydrogen Bonding in Liquid WaterJournal of the American Chemical Society, 2007
- Dynamics of Water in Biological RecognitionChemical Reviews, 2004
- Negligible Effect of Ions on the Hydrogen-Bond Structure in Liquid WaterScience, 2003
- Zur Lehre von der Wirkung der SalzeNaunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie, 1888