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Updated: Jul 17, 2026

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
Time-resolved observation of the Eigen cation in liquid water
Wafa Amir1, Guilhem Gallot, François Hache
1Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, 91128 Palaiseau, France.
Abstract:
Experimental observation and time relaxation measurement of the hydrated proton Eigen form [H(3)O(+)(H(2)O)(3)] are presented here. Vibrational time-resolved spectroscopy is used with an original method of investigating the proton excess in water. The anharmonicity of the time-resolved spectra is characteristic of the Eigen-type proton geometry. Proton relaxation occurs in less than 200 fs. A calculation of the potential energy confirms the experimental result and the Eigen cation lifetime is in good agreement with previous molecular dynamics simulations.
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