Time-dependent water dynamics in hydrated uranyl fluoride [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 2015. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 61-71 : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory, United States. Department of Energy. Office of Science, and United States. Department of Energy. Office of Scientific and Technical Information
- In this study, uranyl fluoride is a three-layer, hexagonal structure with significant stacking disorder in the c-direction. It supports a range of unsolved ‘thermodynamic’ hydrates with 0–2.5 water molecules per uranium atom, and perhaps more. However, the relationship between water, hydrate crystal structures, and thermodynamic results, collectively representing the chemical pathway through these hydrate structures, has not been sufficiently elucidated. We used high-resolution quasielastic neutron scattering to study the dynamics of water in partially hydrated uranyl fluoride powder over the course of 4 weeks under closed conditions. The spectra are composed of two quasielastic components: one is associated with translational diffusive motion of water that is approximately five to six times slower than bulk water, and the other is a slow (on the order of 2–300 ps), spatially bounded water motion. The translational component represents water diffusing between the weakly bonded layers in the crystal, while the bounded component may represent water trapped in subnanometre ‘pockets’ formed by the space between uranium-centred polymerisation units. Complementary neutron diffraction measurements do not show any significant structural changes, suggesting that a chemical conversion of the material does not occur in the thermodynamically isolated system on this timescale.
- Published through SciTech Connect., 09/15/2015., Molecular Physics 114 1 ISSN 0026-8976 AM, and Andrew J. Miskowiec; Anderson, Brian; Herwig, Kenneth; Huq, Ashfia [ORNL]; Mamontov, Eugene [ORNL]; Rondinone, Adam; Trowbridge, Lee.
- Funding Information:
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