Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
216132 | The Journal of Chemical Thermodynamics | 2011 | 12 Pages |
The form of multicomponent Fickian diffusion coefficients matrix in thermodynamically stable mixtures is established based on the form of phenomenological coefficients and thermodynamic factors. While phenomenological coefficients form a symmetric positive definite matrix, the determinant of thermodynamic factors matrix is positive. As a result, the Fickian diffusion coefficients matrix has a positive determinant, but its elements — including diagonal elements — can be negative. Comprehensive survey of reported diffusion coefficients data for ternary and quaternary mixtures, confirms that invariably the determinant of the Fickian diffusion coefficients matrix is positive.
► Irreversible thermodynamics establishes form of multicomponent diffusion coefficients. ► Phenomenological coefficients and thermodynamic factors affect sign of diffusion coefficients. ► Negative diagonal elements of diffusion coefficients matrix can occur in non-ideal mixtures. ► Eigenvalues of the matrix of Fickian diffusion coefficients may not be all real.