Widom Line for the Liquid鈥揋as Transition in Lennard-Jones System

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• 作者：V. V. Brazhkin ; Yu. D. Fomin ; A. G. Lyapin ; V. N. Ryzhov ; E. N. Tsiok
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：December 8, 2011
• 年：2011
• 卷：115
• 期：48
• 页码：14112-14115
• 全文大小：790K
• 年卷期：v.115,no.48(December 8, 2011)
• ISSN：1520-5207

文摘

The locus of extrema (ridges) for heat capacity, thermal expansion coefficient, compressibility, and density fluctuations for model particle systems with Lennard-Jones (LJ) potential in the supercritical region have been obtained. It was found that the ridges for different thermodynamic values virtually merge into a single Widom line at T < 1.1Tb>cb> and P < 1.5Pb>cb> and become practically completely smeared at T < 2.5Tb>cb> and P < 10Pb>cb>, where Tb>cb> and Pb>cb> are the critical temperature and pressure. The ridge for heat capacity approaches close to critical isochore, whereas the lines of extrema for other values correspond to density decrease. The lines corresponding to the supercritical maxima for argon and neon are in good agreement with the computer simulation data for LJ fluid. The behavior of the ridges for LJ fluid, in turn, is close to that for the supercritical van der Waals fluid, which is indicative of a fairly universal behavior of the Widom line for a liquid鈥揼as transition.