Thermodynamic properties of the freely jointed tangent homonuclear Yukawa chain fluid

Recently, a simple analytical expression for the first coordination shell (1 ≤ x ≤ 2) of the average site–site intermolecular radial distribution function (ASSIRDF) of the freely jointed tangent hard sphere chain (FJTHSC) fluid has been proposed. This expression was used in the framework of the second-order Barker–Henderson perturbation theory together with the site–site intermolecular hard-core Yukawa potential in order to obtain an equation of state (EOS) for the freely jointed tangent Yukawa chain (FJTYC) fluid. The derived EOS was used for calculating the thermodynamic properties of the FJTYC fluid, with the attraction of variable range, such as compressibility factor, vapor–liquid equilibria and critical constants. The calculated compressibility factors, above the critical temperature, were compared with the available simulation data and the results of the well-known theories for a wide range of densities, temperatures and different values of attractive ranges. The overall agreement was good and the accuracy of the results could compete with the accuracy of those obtained using very famous theories and equations of state in the literature such as the statistical associate fluid theory with the interaction of variable range (SAFT-VR).