Scaling, Crossover, and Classical Behavior in the Order Parameter Equation for Coexisting Phases of Benzene from Triple Point to Critical Point

摘要

The temperature dependence of the density along the coexistence curve of benzene in the vicinity of the critical point and in a wide temperature range down to the triple point was investigated. The original results as well as literature data were statistically treated. A regression analysis of data on the critical exponents and critical amplitudes used as fitting parameters in a model equations was carried out. An adequate description of the order parameter by the three-term scaling equation in the entire two-phase (liquid-gas) region of benzene was obtained with experimental values of β_0 =0.352 ± 0.003 and Δ = 1.3 ± 0.2, which are inconsistent with the Ising model (β_0 = 0.325) and the Wegner exponent (Δ = 0.5), respectively. It is shown that the equation with fixed classical exponents does not adequately describe the experimental data even far from the critical point.