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arXiv 2103.06241cond-mat.softcond-mat.stat-mechphysics.chem-phphysics.comp-phphysics.flu-dyn
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平衡经典液体中的准固态微观动力学:自洽弛豫理论

Quasi-solid state microscopic dynamics in equilibrium classical liquids: Self-consisnent relaxation theory

A. V. Mokshin, R. M. Khusnutdinoff, Ya. Z. Vilf, B. N. Galimzyanov

摘要:

在时间关联函数概念的框架内,我们发展了液体中横向集体粒子动力学的自洽弛豫理论。该理论同意众所周知的结果在短波(自由粒子动力学)和长波(流体动力学)的限制。我们得到了在波数$k$范围内实现的横向粒子流谱密度~ $C_T(k,ω)$的一般表达式。在域的微观空间尺度相媲美的有效力的粒子间相互作用的作用尺度,该理论再现了一个过渡,从一个政权与典型的平衡液体动力学的集体粒子动力学的属性类似的固态属性出现的政权:有效的剪切刚度和横向(剪切)声波。在相应近似的框架下,我们得到了平衡集体动力学中所有特征区域的横向粒子流谱密度的表达式。我们得到的横向(剪切)声波的色散规律的表达式,以及运动剪切粘度$ν$,横向声速$v^{(T)}$,和相应的声阻尼系数$Γ^{(T)}$的关系。我们比较了理论结果与液态锂在熔点附近的原子动力学模拟结果。

英文摘要:

In the framework of the concept of time correlation functions, we develop a self-consistent relaxation theory of the transverse collective particle dynamics in liquids. The theory agrees with well-known results in both the short-wave (free particle dynamics) and the long-wave (hydrodynamic) limits. We obtain a general expression for the spectral density~$C_T(k,ω)$ of transverse particle current realized in the range of wave numbers $k$. In domain of microscopic spatial scales comparable to action scale of effective forces of interparticle interaction, the theory reproduces a transition from a regime with typical equilibrium liquid dynamics to a regime with collective particle dynamics where properties similar to solid-state properties appear: effective shear stiffness and transverse (shear) acoustic waves. In the framework of the corresponding approximations, we obtain expressions for the spectral density of transverse particle current for all characteristic regimes in equilibrium collective dynamics. We obtain expressions for dispersion law for transverse (shear) acoustic waves and also relations for the kinematic shear viscosity $ν$, the transverse speed of sound $v^{(T)}$, and the corresponding sound damping coefficient $Γ^{(T)}$. We compare the theoretical results with the results of atomic dynamics simulations of liquid lithium near the melting point.

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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