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Updated: Jul 8, 2025

High-Resolution Neutron Spectroscopy to Study Picosecond-Nanosecond Dynamics of Proteins and Hydration Water
Published on: April 28, 2022
Molecular structural dynamics in water-ethanol mixtures: Spectroscopy with polarized neutrons simultaneously
Riccardo Morbidini1,2, Robert M Edkins3, Mark Devonport4
1Institut Max von Laue - Paul Langevin, 71 Avenue des Martyrs, F-38042 Grenoble, France.
Abstract:
Binary mixtures of water with lower alcohols display non-linear phase behaviors upon mixing, which are attributed to potential cluster formation at the molecular level. Unravelling such elusive structures requires investigation of hydrogen-bonding sub-nanosecond dynamics. We employ high-resolution neutron time-of-flight spectroscopy with polarization analysis in combination with selective deuteration to study the concentration-dependent structural dynamics in the water rich part of the phase diagram of water-ethanol mixtures. This method enables simultaneous access to atomic correlations in space and time and allows us to separate spatially incoherent scattering probing self-diffusion of the ethanol fraction from the coherent scattering probing collective diffusion of the water network as a whole. Our observations indicate an enhanced rigidity of the hydrogen bond network at the mesoscopic length scale compared to the molecular scale as the ethanol fraction increases, which is consistent with the hypothesis of clusters.
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