Possible Anomalies in Multicomponent Diffusion

The evolution of concentrations in multicomponent diffusion depends on a characteristic parameter Δ constructed in terms of the diffusion coefficients D ik . For ternary diffusion Δ = (D 22 D 11 ) 2 + + 4 D 12 D 21 where D 12 D 21 can have both signs. In the case Δ > 0 one gets the normal monotonous evolution of concentrations, Δ < 0 leads to damped oscillations, at Δ = 0 there appear maxima and minima of concentrations for some values x 2 / t .