diffusion potential

For an ideal dilute solution, $Δ Φ d$ is the integral of $∇ Φ$ (given by the following equation) across the boundary between two regions of different concentrations.

$∇ Φ = R T ∑ D i z i ∇ c i F ∑ s i 2 D i c i$

where $D i$ is the diffusion coefficient of species $i$ , $z i$ is the charge number of species $i$ , $c i$ is the concentration of species $i$ , $R$ is the gas constant, $T$ is the thermodynamic temperature, and $F$ is the Faraday constant.

Source:

PAC, 1981, 53, 1827 (Nomenclature for transport phenomena in electrolytic systems) on page 1838