Heat capacity of liquids: an approach from the solid phase

Heat conduction through a trapped solid: effect of structural changes on thermal conductance

We study the conduction of heat across a narrow solid strip trapped by an external potential and in contact with its own liquid. Structural changes, consisting of addition and deletion of crystal layers in the trapped solid, are produced by altering the depth of the confining potential. Nonequilibrium molecular dynamics simulations and, wherever possible, simple analytical calculations are used to obtain the thermal resistance in the liquid, solid and interfacial regions (Kapitza or contact resistance). We show that these layering transitions are accompanied by sharp jumps in the contact therm…

Degree of dimerization, effective polarizability of molecules and heat capacity of the saturated water vapor

The work is devoted to the investigation of properties of water vapor. The main attention is focused on the physical nature of its effective polarizability and heat capacity at constant volume. We show that the specific temperature dependencies of these characteristics are mainly caused by thermal vibration excitations of water dimers. In connection with this we determine normal coordinates for the dimer vibrations. We investigate fluctuations of the dipole moments of dimers in details and consider their contributions to the dielectric permittivity of the water vapor. We also took into account…

Temperature field and heat generation at the tip of a cutout in a viscoelastic solid body undergoing loading

Using the finite element method we quantitatively analyse temperature field evolution in a viscoelastic solid undergoing a loading--unloading process. In particular we investigate the temperature field inside a Kelvin--Voigt type viscoelastic body with a thin cutout. We find that the viscosity significantly contributes to the temperature field changes, and that the temperature field changes initiated by the loading--unloading process are strongly concentrated at the tip of the thin cutout. The predicted temperature field qualitatively corresponds to the temperature field observed in experiment…

Heat Capacity Effects Associated with the Hydrophobic Hydration and Interaction of Simple Solutes: A Detailed Structural and Energetical Analysis Based on MD Simulations

We examine the SPCE and TIP5P water models to study heat capacity effects associated with the hydrophobic hydration and interaction of Xenon particles. We calculate the excess chemical potential for Xenon employing the Widom particle insertion technique. The solvation enthalpy and excess heat capacity is obtained from the temperature dependence of the chemical potentials and, alternatively, directly by Ewald summation, as well as a reaction field based method. All three different approaches provide consistent results. The reaction field method allows a separation of the individual components t…

Heat capacity at the glass transition

A fundamental problem of glass transition is to explain the jump of heat capacity at the glass transition temperature $T_g$ without asserting the existence of a distinct solid glass phase. This problem is also common to other disordered systems, including spin glasses. We propose that if $T_g$ is defined as the temperature at which the liquid stops relaxing at the experimental time scale, the jump of heat capacity at $T_g$ follows as a necessary consequence due to the change of system's elastic, vibrational and thermal properties. In this picture, we discuss time-dependent effects of glass tra…

基于经典与量子模拟的水热容量异常的结构起源

Structural Origin of Water Heat Capacity Anomaly from Classical and Quantum Simulations

研究水热容量异常的结构起源，采用经典和路径积分分子动力学方法，发现核量子效应抑制高频振动，热容量异常源于结构波动，通过两态映射揭示有效焓标度，建立微观联系。

液体声子理论的另一种方法：Frenkel频率和热容随压力和温度变化的解析研究

An alternative approach to the phonon theory of liquids: An analytical study of Frenkel frequency and heat capacity as a function of pressure and temperature

本文提出一种无需黏度数据、基于化学势和扩散平衡计算Frenkel频率的新方法，推导出液体热容随温度和压力变化的解析表达式，并在四种惰性液体中验证了模型准确性。

Heat capacity of liquids in light of hydrodynamics as U(1) gauge theory

We investigate the heat capacity of liquids through a theoretical approach based on a quasiparticle description. By interpreting the microscopic dynamics of particles in liquids in terms of quasiparticles, we suggest a simplified understanding of the number of degrees of freedom in liquids. A equivalence between hydrodynamics and U(1) gauge theory, which is newly proposed in the present paper, develops the quasiparticle description to construct a new Lagrangian which correctly reproduces the number of modes at the melting points and at the critical points. The heat capacity evaluated from this…

Heat capacity of square-well fluids of variable width

We have obtained by Monte Carlo NVT simulations the constant-volume excess heat capacity of square-well fluids for several temperatures, densities and potential widths. Heat capacity is a thermodynamic property much more sensitive to the accuracy of a theory than other thermodynamic quantities, such as the compressibility factor. This is illustrated by comparing the reported simulation data for the heat capacity with the theoretical predictions given by the Barker-Henderson perturbation theory as well as with those given by a non-perturbative theoretical model based on Baxter's solution of the…

密集液体的比热容：两相模型与熔点温度标度之间的联系

Heat capacity of dense liquids: A link between two-phase model and melting temperature scaling

本文通过两相模型揭示了液体刚性参数的尺度不变性如何自然导出广义Rosenfeld-Tarazona标度，从而建立比热容与熔点温度标度之间的联系。

薄膜热容的量子限制理论

Quantum confinement theory of the heat capacity of thin films

针对纳米限制下固体热性质缺乏理论的问题，提出薄膜量子限制理论，预测热容温度依赖为~T⁴且随膜厚线性增长，与NbTiN薄膜实验结果吻合。