On the molecular theory of diffusion and heat conduction in multicomponent solutions

A statistical mechanical analysis is presented of diffusion and heat conduction in multicomponent systems. Explicit molecular expressions are derived for the generalized wave vector and frequency dependent Onsager kinetic coefficients and transport coefficients appropriate to various reference frames and specific to several different sets of independent thermodynamic forces. Relationships are established among the coefficients referred to different flow reference frames and to the lab frame coefficients as well. It is shown that the reciprocal relations are fulfilled only for certain very specific sets of independent thermodynamic forces.