ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The densities of the coexisting phases and the capillary length have been measured to obtain the interfacial tension (σ) near the consolute temperatures Tc of the three binary liquid mixtures: triethylamine+water, triethylamine+heavy water, and methanol+cyclohexane. Our data are combined with data from the literature to test predictions for three temperature-independent "universal'' ratios: U+1=σ(ξ+)2/(kBTc) and Y(±)=σ(αt2C±s/kB) −2/3/(kBT0). [Here ξ+ is the correlation length, C±s is the singular part of the heat capacity per unit volume, α=0.11 is the exponent characterizing the specific heat divergence, and t≡(T−Tc)/Tc]. Near Tc, the new experimental values of Y(+) range from 5.5–5.8 in agreement with the value 5.6 obtained by Moldover [Phys. Rev. 31, 1022 (1985)] in a review of earlier experiments. However, the experimental values of Y(+) are inconsistent with either the value Y(+)=4.4±0.4 obtained from a recent simulation of the simple-cubic Ising model or the value Y(+)=2.6–3.0 obtained from a one-loop renormalization group calculation. The experimental values Y(−)=3.7 and U+1 =0.39 are also much larger than both the Ising model and the renormalization group values. It is unlikely that the inconsistency between the experimental and the theoretical ratios Y(±) and U+1 can be explained by systematic errors in the measurements of σ, because diverse techniques for measuring σ have yielded consistent results for a wide variety of fluid systems. A table of the relevant amplitudes for 16 fluid systems is included.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.451619
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