Statistical mechanics model for the transit free energy of monatomic liquids

Abstract

In applying Vibration-Transit (V-T) theory of liquid dynamics to the thermodynamic properties of monatomic liquids, the point has been reached where an improved model is needed for the small (approx. 10%) transit contribution. Toward this goal, an analysis of the available high-temperature experimental entropy data for elemental liquids was recently completed [D. C. Wallace, E. D. Chisolm, and N. Bock, Phys. Rev. B 79, 051201 (2009)]. This analysis yields a common curve of transit entropy vs. T/θ_{tr}, where T is temperature and θ_{tr} is a scaling temperature for each element. In the present paper, a statistical mechanics model is constructed for the transit partition function, and is calibrated to the experimental transit entropy curve. The model has two scalar parameters, and captures the temperature scaling of experiment. The calibrated model fits the experimental liquid entropy to high accuracy at all temperatures. With no additional parameters, the model also agrees with both experiment and molecular dynamics for the internal energy vs. T for Na. With the calibrated transit model, V-T theory provides equations subject to ab initio evaluation for thermodynamic properties of monatomic liquids. This will allow the range of applicability of the theory, and its overall accuracy, to be determined. More generally, the hypothesis of V-T theory, which divides the many-atom potential energy valleys into random and symmetric classes, can also be tested for its application beyond monatomic systems.

8 pages, 3 figures, small changes to correspond to published version

References in corpus (8)

• On the constitution of sodium at higher densities
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• Non--Adiabatic Contributions to the Free Energy from the Electron--Phonon Interaction for Na, K, Al, and Pb
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• An improved model for the transit entropy of monatomic liquids

Cited by in corpus (4)

• First-principles calculation of entropy for liquid metals
• Liquid state properties from first principles DFT calculations: Static properties
• Atomic Motion from the Mean Square Displacement in a Monatomic Liquid
• V-T theory for the Self-Intermediate Scattering Function in a Monatomic Liquid