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arXiv 1208.3265cond-mat.stat-mech
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从临界点到三相点的热力学曲率

Thermodynamic curvature from the critical point to the triple point

George Ruppeiner

摘要:

我评估的热力学曲率$R$十四纯流体沿其液体-蒸气共存曲线,从临界点到三相点,使用NIST化学网络书的热力学输入。在这一广泛的概述中,$R$在共存的液相和气相中进行评价。$R$是一个不变量,其大小$|R|$是流体中介观组织结构尺寸的度量,其符号指定分子间相互作用是有效吸引($R<0$)还是排斥($R>0$)。我讨论了纯流体中$R$的五个原理:1)在临界点附近,相互作用的吸引部分形成松散结构,其尺寸$|R|$与相关体积$ξ^3$成比例,并且$R$的符号为负,2)在气相中,存在大小为$|R|$的紧凑簇的实例,其由相互作用的吸引部分形成,并且由相互作用的排斥部分防止崩溃。相互作用和$R$正的符号,3)在渐近临界点状态中,共存的液相和气相中的$R$彼此相等,即,4)在渐近临界点范围之外,不相称的$R$可能与亚稳性有关,5)致密液相具有分子体积数量级的$|R|$,对于通过吸引相互作用保持在一起的类液体状态,$R$的符号为负,而对于通过排斥相互作用保持在一起的类固体状态,$R$的符号为正。这些考虑扩大和扩展了热力学曲率在纯流体中的应用。

英文摘要:

I evaluate the thermodynamic curvature $R$ for fourteen pure fluids along their liquid-vapor coexistence curves, from the critical point to the triple point, using thermodynamic input from the NIST Chemistry WebBook. In this broad overview, $R$ is evaluated in both the coexisting liquid and vapor phases. $R$ is an invariant whose magnitude $|R|$ is a measure of the size of mesoscopic organized structures in a fluid, and whose sign specifies whether intermolecular interactions are effectively attractive ($R<0$) or repulsive ($R>0$). I discuss five principles for $R$ in pure fluids: 1) near the critical point, the attractive part of the interactions forms loose structures of size $|R|$ proportional to the correlation volume $ξ^3$, and sign of $R$ negative, 2) in the vapor phase, there are instances of compact clusters of size $|R|$ formed by the attractive part of the interactions and prevented from collapse by the repulsive part of the interactions, and sign of $R$ positive, 3) in the asymptotic critical point regime, the $R$'s in the coexisting liquid and vapor phases are equal to each other, i.e., commensurate, 4) outside the asymptotic critical point regime incommensurate $R$'s may be associated with metastability, and 5) the compact liquid phase has $|R|$ on the order of the volume of a molecule, with sign of $R$ negative for a liquidlike state held together by attractive interactions and sign of $R$ positive for a solidlike state held up by repulsive interactions. These considerations amplify and extend the application of thermodynamic curvature in pure fluids.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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