Dynamical critical phenomena in chemically reactive fluid mixtures

It is shown that the interplay between chemical reactions and thermodynamic stability gives rise to some novel phenomena manifested in a slowing down of the chemical reaction and in changes in the critical behavior of transport processes. In an n-component fluid, when all the components participate in the reaction, the rate vanishes near the critical point Tc as [(T-Tc)Tc], where 1.25. When one of the components does not participate in the reaction, the rate vanishes, in general, as [(T-Tc)Tc]a, where a0.12. If more than one component is nonreactive the rate of the reaction is not sensitive to the approach to Tc. Reactive binary mixtures are treated in detail on the basis of a mode-coupling theory. In contrast to nonreactive mixtures, the shear viscosity has no divergence near the critical point. In addition, the diffusion coefficient has a different temperature and wave-vector dependence.