Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-bonded Liquid
- ORNL
- ISIS Facility, Rutherford Appleton Laboratory
- CSIC - Inst. Estructura de la Materia & Dept. of Electricity and Electronics
- University of Tennessee, Knoxville (UTK)
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.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 978744
- Journal Information:
- Physical Review Letters, Vol. 98, Issue 7; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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