The Stokes-Einstein law, which expresses the diffusion coefficient in terms of solvent viscosity and solute molecular radius, is based on the assumption that a diffusing ion or molecule moves among solute molecules as a macroscopic entity does in a continuum. Since the small dimension of the diffusing species often renders this assumption untenable, whereas experiments support the validity of the law, a new deduction is proposed, based on elementary macroscopic laws of thermodynamics, hydrodynamics and diffusion. Comparison of the laws by Fick and by Hagen and Poiseuille results in the Stokes-Einstein formula.
|Number of pages||2|
|Journal||Radiation Physics and Chemistry|
|Publication status||Published - jan. 1 1991|
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