Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-Bonded Liquid
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)
- CSIC-Instituto Estructura de la Materia and Department of Electricity and Electronics, University Basque Country, P.O. Box 644, Bilbao 48080 (Spain)
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600 (United States)
- Spallation Neutron Source, Oak Ridge National Laboratory, Scarboro Road, Oak Ridge, Tennessee 37830 (United States)
Quasielastic neutron scattering has been used to investigate the single-particle dynamics of hydrogen fluoride across its entire liquid range at ambient pressure. For T>230 K, translational diffusion obeys the celebrated Stokes-Einstein relation, in agreement with nuclear magnetic resonance studies. At lower temperatures, we find significant deviations from the above behavior in the form of a power law with exponent {xi}=-0.71{+-}0.05. More striking than the above is a complete breakdown of the Debye-Stokes-Einstein relation for rotational diffusion. Our findings provide the first experimental verification of fractional Stokes-Einstein behavior in a hydrogen-bonded liquid, in agreement with recent computer simulations [S. R. Becker et al., Phys. Rev. Lett. 97, 055901 (2006)].
- OSTI ID:
- 20955477
- Journal Information:
- Physical Review Letters, Vol. 98, Issue 7; Other Information: DOI: 10.1103/PhysRevLett.98.077801; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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