Comparison of definitions of ordinary diffusion coefficients in multi-component mixture

Concentrating our attentions on the definitions of diffusion coefficients in multi-component mixture, we have compared two theories given by Hirschfelder et al. and by Chapman-Cowling. Differences between the two definitions of diffusion coefficients are clarified with respect to (i) treatment for removing a degree of indeterminacy of the coefficients, (ii) condition for mass balances and (iii) symmetric relation. Moreover, an expression of Chapman-Cowling coefficients was obtained in terms of those by Hirschfelder et al. The relation and the inverse, derived before by Ern et al., enable us to exchange mutually the two coefficients. (author)