Department of Chemistry, East China University of Science and Technology, Shanghai 200237, China.
J Chem Phys. 2010 Feb 21;132(7):074501. doi: 10.1063/1.3308474.
The upper critical temperatures (T(U)) and the lower critical temperatures (T(L)) were precisely determined for 11 quasiternary solutions of water +n-decane and +n-undecane +tert-butanol with various mass ratios of n-decane to n-undecane. Measurements of angular dependence of the scattered light intensity for each of the three liquid coexisting phases and each of the 11 solutions at the middle temperatures T(m)=(T(U)+T(L))/2 are reported. From the light scatting data, the zero-angle scattering intensities I(0) and the correlation lengths xi at T(m) in each of the phases were calculated and used to test the Griffiths sum rules. It was found that (DeltaT)(2/3) (where DeltaT=T(U)-T(L)) is a good thermodynamic field to measure the distance from the tricritical point, and the second sum is converged to zero with a proportionality to (DeltaT)(2/3) as the system approaches the tricritical point, which is in agreement with what the classical asymptotic theory predicted. However the first sums are neither zero nor constant, they are significantly curved and unambiguously diverged as strongly as does an individual susceptibility, which evidences that the amplitude ratios are nonclassical.
准确测定了水+n-癸烷和+n-十一烷+叔丁醇的 11 种准四元溶液在不同的 n-癸烷与 n-十一烷质量比下的上临界温度（T(U)）和下临界温度（T(L））。报道了在中间温度 T(m)=(T(U)+T(L))/2 下，三个共存液相和 11 种溶液中的每一种的散射光强度角依赖性的测量结果。从光散射数据中，计算了在每个相中在 T(m)时的零角散射强度 I(0)和相关长度 xi，并用于检验 Griffiths 求和规则。结果发现，(DeltaT)(2/3)（其中 DeltaT=T(U)-T(L））是测量与三叉点距离的一个很好的热力学场，并且随着系统接近三叉点，第二求和项收敛到零，与 (DeltaT)(2/3)成正比，这与经典渐近理论的预测一致。然而，第一求和项既不是零也不是常数，它们显著弯曲，并且像单个磁化率一样明显发散，这表明幅度比是非经典的。
