ISIS Neutron and Muon Source Data Journal

Experimental investigation into aqueous electrolyte clustering at sub-saturation concentrations

Abstract: Recently, experimental investigations utilising the Surface Force Apparatus (SFA) into highly concentrated simple 1:1 electrolyte solutions have revealed a peculiar long-ranged correlation length larger than the Debye screening length. We have recently modified the Restricted Primitive Model via ion hydration shells. Our systems displayed significant clustering at concentrations comparable to experimental SFA conditions. We have demonstrated that a long-ranged decay observed in our system results from cluster formation. We have conducted experimental investigations using SAXS on sub-saturation and saturated simple electrolyte solutions. An anomalous and reproducible structural peak was identified at q = 0.015 Å^-1. This peak appears to be q-invariant with respect to different salts used in the investigation. The scattering pattern displays horizontal anisotropy. The primary aim for our proposed NIMROD experiment is to experimentally investigate the existence of sub-saturation cluster formation. We aim at measuring the RDFs between ions in high resolution. Additionally, we aim at directly observing the scattering patterns emerging from hypothesized clusters, thanks to NIMROD's wide accessible q-range. We hypothesise that the effective correlation lengths extracted in SFA experiments are in fact density correlations originating from cluster formation. Thus, a direct experimental observation of these hypothesised clusters would strongly support our hypothesis.

Principal Investigator: Mr David Ribar
Experimenter: Professor Marie Skepö
Experimenter: Professor Jan Forsman
Local Contact: Dr Tom Headen

DOI: 10.5286/ISIS.E.RB2510006

ISIS Experiment Number: RB2510006

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Mr David Ribar et al; (2025): Experimental investigation into aqueous electrolyte clustering at sub-saturation concentrations, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2510006

Data is released under the CC-BY-4.0 license.