Stokes−Einstein−Debye failure in molecular orientational diffusion: exception or rule?

Turton, D. and Wynne, K. (2014) Stokes−Einstein−Debye failure in molecular orientational diffusion: exception or rule? Journal of Physical Chemistry B, 118(17), pp. 4600-4604. (doi: 10.1021/jp5012457)

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The Stokes–Einstein–Debye (SED) expression is used routinely to relate orientational molecular diffusivity quantitatively to viscosity. However, it is well-known that Einstein’s equations are derived from hydrodynamic theory for the diffusion of a Brownian particle in a homogeneous fluid and examples of SED breakdown and failure for molecular diffusion are not unusual. Here, using optical Kerr-effect spectroscopy to measure orientational diffusion for solutions of guanidine hydrochloride in water and mixtures of carbon disulfide with hexadecane, we show that these two contrasting systems each show pronounced exception to the SED relation and ask if it is reasonable to expect molecular diffusion to be a simple function of viscosity.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Turton, Dr David and Wynne, Professor Klaas
Authors: Turton, D., and Wynne, K.
Subjects:Q Science > QC Physics
Q Science > QD Chemistry
College/School:College of Science and Engineering > School of Chemistry
Research Group:Ultrafast chemical physics
Journal Name:Journal of Physical Chemistry B
Publisher:American Chemical Society
ISSN (Online):1520-5207
Copyright Holders:Copyright © 2014 American Chemical Society
First Published:First published in Journal of Physical Chemistry B 118(17):4600-4604
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
559071Two-dimensional terahertz/IR spectroscopy: a unique probe of ultrafast hydrogen-bond dynamics of liquid water and model systems.Klaas WynneEngineering & Physical Sciences Research Council (EPSRC)EP/F06926X/1CHEM - CHEMISTRY
582891The structure and dynamics of water confined in nanoscale pools: the dynamic crossoverKlaas WynneEngineering & Physical Sciences Research Council (EPSRC)EP/J009733/1CHEM - CHEMISTRY