Generalized corresponding states model for bulk and interfacial properties in pure fluids and fluid mixtures

We have formulated a general approach for transforming an analytical equation of state ~EOS! into the crossover form and developed a generalized cubic ~GC! EOS for pure fluids, which incorporates nonanalytic scaling laws in the critical region and in the limit r→0 is transformed into the ideal gas equation EOS. Using the GC EOS as a reference equation, we have developed a generalized version of the corresponding states ~GCS! model, which contains the critical point parameters and accentric factor as input as well as the Ginzburg number Gi. For nonionic fluids we propose a simple correlation between the Ginzburg number Gi and Zc , v, and molecular weight M w . In the second step, we develop on the basis of the GCS model and the density functional theory a GCS-density functional theory ~DFT! crossover model for the vapor–liquid interface and surface tension. We use the GCS-DFT model for the prediction of the PVT, vapor–liquid equilibrium ~VLE! and surface properties of more than 30 pure fluids. In a wide range of thermodynamic states, including the nearest vicinity of the critical point, the GCS reproduces the PVT and VLE surface and the surface tension of one-component fluids ~polar and nonpolar! with high accuracy. In the critical region, the GCS-DFT predictions for the surface tension are in excellent agreement with experimental data and theoretical renormalization-group model developed earlier. Using the principle of the critical-point universality we extended the GCS-DFT model to fluid mixtures and developed a field-variable based GCS-FV model. We provide extensive comparisons of the GCS-FV model with experimental data and with the GCS-XV model formulated in terms of the conventional density variable— composition. Far from the critical point both models, GCS-FV and GCS-XV, give practically similar results, but in the critical region, the GCS-FV model yields a better representation of the VLE surface of binary mixtures than the GCS-XV model. We also show that by considering the Ginzburg number Gi as an independent CS parameter the GCS model is capable of reproducing the phase behavior of finite neutral nuclear matter. © 2003 American Institute of Physics. @DOI: 10.1063/1.1605375#