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arXiv 2101.05936cond-mat.softcond-mat.stat-mech
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高斯核模型流体的热力学几何

Thermodynamic geometry of the Gaussian core model fluid

George Ruppeiner, Peter Mausbach, Helge-Otmar May

摘要:

软物质系统的三维高斯核模型(GCM)具有排斥的粒子间相互作用势$ϕ(r) = \varepsilon\, {\rm exp}\left[ -(r/σ)^{2} \right]$,其中$r$是一对原子之间的距离,正常数$\varepsilon$和$σ$分别设定能量和长度尺度。$ϕ(r)$在性质上主要是软的,没有流体模型中存在的典型硬核。我们工作的热力学Ricci曲率标量$R$的GCM,特别注意的符号$R$,这是根据以前的结果,预计是积极的/消极的微观相互作用排斥/吸引。在大多数的热力学相空间,$R$被发现是积极的,与$σ^3$的顺序值。然而,在低密度和低温度下,GCM势呈现出硬球排斥系统的特征,并且发现$R$具有反常的负号。这样的迹象也发现较早的逆幂律势在硬球极限,似乎是一个持久的功能硬球模型。

英文摘要:

The three-dimensional Gaussian core model (GCM) for soft-matter systems has repulsive interparticle interaction potential $ϕ(r) = \varepsilon\, {\rm exp}\left[ -(r/σ)^{2} \right]$, with $r$ the distance between a pair of atoms, and the positive constants $\varepsilon$ and $σ$ setting the energy and length scales, respectively. $ϕ(r)$ is mostly soft in character, without the typical hard core present in fluid models. We work out the thermodynamic Ricci curvature scalar $R$ for the GCM, with particular attention to the sign of $R$, which, based on previous results, is expected to be positive/negative for microscopic interactions repulsive/attractive. Over most of the thermodynamic phase space, $R$ is found to be positive, with values of the order of $σ^3$. However, for low densities and temperatures, the GCM potential takes on the character of a hard-sphere repulsive system, and $R$ is found to have an anomalous negative sign. Such a sign was also found earlier in inverse power law potentials in the hard-sphere limit, and seems to be a persistent feature of hard-sphere models.

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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