Transport coefficients and the spinodal of a fluid.

Based on the results of computer simulation of transport coefficients in a Lennard-Jones fluid, it has been shown that in (p,T) coordinates, lines of constant values of coefficients of self-diffusion D and excess shear viscosity Δη extended into the region of superheated liquid and supersaturated vapor have an envelope. Each of the ensembles of such lines is divided into two parts by a critical isoline, where the conditions φ = φc = const (φ = D,Δη) are fulfilled. One part of this ensemble has as an envelope the branch of the spinodal that refers to superheated liquid; the other part has the branch of the spinodal of supersaturated vapor. The critical point of liquid-vapor equilibrium is the cusp of the spinodal, at which the critical isolines have a common tangent line with the spinodal and the binodal. Thus, at the approach to the spinodal, the relations (∂D/∂p)(T) → ∞ and (∂Δη/∂p)(T) → ∞ hold.