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Updated: Mar 26, 2026
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Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
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Probing ion-specific effects on aqueous acetate solutions: Ion pairing versus water structure modifications
Tristan Petit1, Kathrin M Lange1, Gerrit Conrad1
1Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.
Structural Dynamics (Melville, N.Y.)
|January 23, 2016
Summary
Monovalent cations like lithium and potassium alter water structure by affecting hydrogen bonds. These changes in water
Area of Science:
- Physical Chemistry
- Aqueous Solutions
- Spectroscopy
Background:
- Understanding how ions affect water structure is crucial in various chemical and biological processes.
- Monovalent cations are common in natural and industrial systems, influencing solution properties.
- Previous studies have explored ion-water interactions, but detailed structural insights remain an active research area.
Purpose of the Study:
- To investigate the impact of different monovalent cations (Li+, K+, NH4+, Na+) on the hydrogen bond network of water.
- To characterize cation- and counterion-dependent modifications in aqueous chloride and acetate solutions.
- To explore ion pairing in acetate solutions using advanced spectroscopic techniques.
Main Methods:
- Oxygen K-edge X-ray absorption spectroscopy (XAS) of a liquid microjet.
- X-ray emission spectroscopy (XES) to probe electronic structure.
- Resonant inelastic X-ray scattering (RIXS) for detailed analysis of water structure and ion interactions.
Main Results:
- Observed distinct effects of various monovalent cations on the oxygen K-edge emission spectra, indicating modified water hydrogen bonding.
- Demonstrated ion- and counterion-specific alterations in the water structure.
- Provided evidence for ion pairing between cations and carboxylates in acetate solutions, characterized by XAS and RIXS.
Conclusions:
- The study reveals that monovalent cations significantly influence water's hydrogen bond network in a cation-dependent manner.
- Experimental findings correlate with speciation data and the salting-out properties of the investigated cations.
- Advanced X-ray spectroscopy techniques offer powerful insights into ion-water interactions and solution behavior.
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