Microstructural heterogeneities arising from molecular clusters directly affect the nonlinear thermodynamic properties of supercritical fluids. We present a physical model to elucidate the relation between energy exchange and heterogeneous cluster dynamics during the transition from liquidlike to gaslike conditions. By analyzing molecular-dynamics data and employing physical principles, the model considers contributions from three key processes, namely, changing cluster density, cluster separation, and transfer of molecules between clusters. We show that the proposed model is consistent with the energetics at subcritical conditions and can be used to explain the nonlinear behavior of thermodynamic response functions, including the peak in the isobaric heat capacity. Published by the American Physical Society 2024

中文翻译：

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超临界流体中的非均相团簇能量学和非线性热力学响应


分子团簇产生的微观结构异质性直接影响超临界流体的非线性热力学性质。我们提出了一个物理模型来阐明从液体到气态条件过渡期间能量交换和非均质团簇动力学之间的关系。通过分析分子动力学数据并采用物理原理，该模型考虑了三个关键过程的贡献，即改变团簇密度、团簇分离和分子团簇之间的转移。我们表明，所提出的模型与亚临界条件下的能量学一致，可用于解释热力学响应函数的非线性行为，包括同量异位热容的峰值。 美国物理学会 2024 年出版