Quantum effects on the temperature dependence of surface tension of simple liquids

Abstract

An equation of general applicability is proposed to describe the surface tension of simple liquids over an extended temperature range. This equation incorporates the quantum effects on the exponent μ, which characterizes the temperature dependence of surface tension. Far from the critical region, μ decreases with increasing de Boer parameter and appears to reach a constant value μ≃1 for He4 and He3. It is pointed out that for quantum liquids μ crosses over to the nonquantum mechanical value of μ≃1.28 as the critical point is approached. The surface tension and its temperature dependence are predicted for hydrogen isotopes such as T2, DT, D2, HT, and HD.

Surface tension of quantum fluids from molecular simulations

“…For example, Sinha and co-workers pointed out that the method developed by Hirshfelder et al based on the de Boer parameter predicts that the surface tension of both classical and quantum liquids have the same temperature dependence, but that this is contradicted by experimental observations. 12 The methods proposed by Frisch and Nielaba 13 and by Hooper and Nordholm 11 do not give quantitative agreement with experiments for some important quantum fluids such as He and H 2 . The method for computing surface tension given by Sinha et al does work quite well for hydrogen isotopes.…”

“…The method for computing surface tension given by Sinha et al does work quite well for hydrogen isotopes. 12 However, this method is not strictly predictive because it relies on parameter fitting to experimental data. 12 Molecular simulations have been used since 1974 to compute vapor liquid surface tension.…”

“…12 However, this method is not strictly predictive because it relies on parameter fitting to experimental data. 12 Molecular simulations have been used since 1974 to compute vapor liquid surface tension. 14,15 All previous surface tension simulations have involved classical fluids.…”

Studies of nucleation and heat transfer in liquid helium isotopes 3 and 4

“…I, which With the exception of the data points for He which represent our own work, this curve is taken from Fig. 4 of Sinha, 1982c. 1.0 reduced bath pressure,'p/p c ' for several classical and quantum liquids. This deviation does not represent a breakdown in the classical corresponding states theory so much as a reflection of the relatively larger quantum mechanical influence on the thermophysical properties of the quantum liquids.…”

“…Indeed, the magnitude of these deviations has been simply scaled to the de Boer parameter in a quantum extension to this theory of corresponding states (Sinha 1982b). One of the successes of this approach was the prediction of the homogeneous nucleation temperatures and other properties (Sinha 1982c) (Skripov 1979, Apfel 1971).…”