Theories of transport properties using the onsager treatment

Abstract

The fundamental equations of the Onsager approach of transport properties in linear response are summarized. From a reformulation of the part of the ion pair distribution function which is perturbed by the ionic velocities, an echo formulation for tracer diffusion is derived which can be compared with former similar results obtained for conductance. It clearly appears that these two different transport processes are in agreement with the original Bjerrum formulation of ionic association for excess thermodynamic properties at equilibrium which can be derived from the Mayer activity expansion.It is finally shown how the Pikal equation for chemical diffusion can be reformulated to reach a final expression also in complete agreement with a Bjerrum formulation. The improvement in overall efficiency of these echo formulations for ions of higher charges and for solvents of lower dielectric constants is emphasized as well as their evident ability to be easily extended to more realistic models for ionic interactions than the restricted primitive model. © 1985 IUPAC