EQUATION OF STATE FOR A BINARY MIXTURE OF HARD-SPHERE FLUIDS WITH CONCENTRATION DEPENDENT CAVITY

An equation of state for a fluid is derived by using an expression [GRAPHICS] where RBAR(j)c = RBAR(j)(1 + alpha-j(X)1X2), beta = 1/kappa-T, X(j) = N(j)/N, and alpha-j is an arbitrary interaction parameter relating to perturbed (RBAR(j)c) and unperturbed (RBAR(j) cavity radii, for the work done in creation of a cavity (solute sphere) in a fluid. The equation is used to calculate as an illustration, sound velocities in a mixture of tetrahydropyrrole and cyclohexane. The agreement between these values with those obtained experimentally is striking.