Self-diffusion

Self-diffusion

According to the 2^nd edition of the IUPAC Compendium of Chemical Terminology (1997), self-diffusion coefficient is the diffusion coefficient $D_i^*$ of species $i$ when the chemical potential gradient equals zero. It is linked to the diffusion coefficient $D i$ by the equation:

$D_i^*=D_i\frac{\partial\ln c_i}{\partial\ln a_i}.$

Here, $a i$ is the activity of the species $i$ in the solution and $c i$ is the concentration of $i$ .

See also