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Title: Nanometer-sized dynamic entities in an aqueous system

Using neutron spin-echo and backscattering spectroscopy, we have found that at low temperatures water molecules in an aqueous solution engage in center-of-mass dynamics that are different from both the main structural relaxations and the well-known localized motions in the transient cages of the nearest neighbor molecules. While the latter localized motions are known to take place on the picosecond time scale and Angstrom length scale, the slower motions that we have observed are found on the nanosecond time scale and nanometer length scale. They are associated with the slow secondary relaxations, or excess wing dynamics, in glass-forming liquids. Our approach, therefore, can be applied to probe the characteristic length scale of the dynamic entities associated with slow dynamics in glass-forming liquids, which presently cannot be studied by other experimental techniques.
Authors:
 [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1185561
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 17; Journal Issue: 6; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY Water; Liquid dynamics; Neutron scattering