According to IUPAC definition,[1] self-diffusion coefficient is the diffusion coefficient of species when the chemical potential gradient equals zero. It is linked to the diffusion coefficient by the equation:

Here, is the activity of the species in the solution and is the concentration of . This term is commonly assumed to be equal to the tracer diffusion determined by watching the movement of an isotope in the material of interest.

See alsoEdit


  1. ^ S. J. Chalk (1997). A. D. McNaught, A. Wilkinson (ed.). "IUPAC Compendium of Chemical Terminology 'The Gold Book'" (2 ed.). Blackwell Scientific Publications.