- Author
- Mulholland, G. W. | Zollweg, J. A. | Sengers, J. M. H. L.
- Title
- Liquid-Vapor Asymmetries in Pure Fluids.
- Coporate
- National Bureau of Standards, Washington, DC Maine Univ., Orono
- Journal
- Journal of Chemical Physics, Vol. 62, No. 7, 2536-2549, April 1, 1975
- Keywords
- fluids | density effects | temperature
- Identifiers
- decorated lattice gas; coexistence curve
- Abstract
- The coexistence curve and the compressibility-like quantity at the coexistence curve are calculated for mermin's decorated lattice gas. We tabulate the pade approximants to the Ising model properties which were used in these calculations. It is shown that for the proper choice of the adjustable parameter in the model the asymmetries in the coexistence curve and in over a large temperature range are qualitatively similar to those in real fluids. Also, similar correlations between the voerall coexistence curvey asymmetry and the amplitudes of divergences for the critical region occur in the model and in real fluids. Based on our model calculations, several predictions for fluid behavior near the critical point are listed: (1) The asymptoic asymmetry in the coexistence curve and in at the coexistence curve should be most observable for fluids with large overall asymmetry such as SF6, NH3, and H2O; (2) the range of the asymptotic asymmetry for is expected to extend somewhat beyond [equation] for such fluids; (3) in order to obtain an estimate for the compressibility exponent gamma' that is within a few percent of the true asymptotic value, experiments will have to be confined to the range [equation]. Recent experimental data for at the coexistence curve are found to be consistent with the model for [equation], but are inconclusive closer to the critical point.