Integral equation study of the residual chemical potential in infinite‐dilution supercritical solutions

A new method for solving the integral equation based on the Ornstein‐Zernike equation for binary mixture is proposed. Then the radial distribution function obtained for both the Percus‐Yevick and the hypernetted chain closure equations are used to calculate the residual chemical potential at infinite‐dilution and at reduced temperatures T* = 2, 1.5 (supercritical isotherms) over a varying range of reduced densities ρ* = 0.1 to 0.6 for various types of the Lennard‐Jones mixture in terms of size ratios D and energy ratios C. To examine the ability of the integral equation approach for the residual chemical potential calculations, the results are compared with the Monte‐Carlo simulation data and the van der Waals I results (Shing et al., 1988). It is seen that at ρ* = 0.1 to 0.5, the deviation of the integral equation results from the MC simulation data is less than the reported statistical fluctuation.