In the following only media which are
isotropic with respect to mass transport (i.e. the transport coefficients are independent of direction) are being considered. In the
linear range (not too far from equilibrium), for uniform temperature and neglecting external fields such as the earth's gravitational field, the flux density of species B is related to the gradients of the electrochemical potentials of all species by the phenomenological equation:
with
where
is the
gradient of the
electrochemical potential of species
i. The proportionality factors
are called phenomenological coefficients. Their values depend on the frame of reference. The latter is taken here to move with the velocity
of species A, and hence:
.
Source:
PAC, 1981, 53, 1827
(Nomenclature for transport phenomena in electrolytic systems)
on page 1830
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
