Microscopic Origins of the Viscosity of a Lennard-Jones Liquid,Physical Review Letters

当前位置： X-MOL 学术 › Phys. Rev. Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Microscopic Origins of the Viscosity of a Lennard-Jones Liquid
Physical Review Letters ( IF 8.1 ) Pub Date : 2022-08-11 , DOI: 10.1103/physrevlett.129.074503
Farid Rizk ₁ , Simon Gelin ₁ , Anne-Laure Biance ₁ , Laurent Joly _{1,

2}

Affiliation

Unlike crystalline solids or ideal gases, transport properties remain difficult to describe from a microscopic point of view in liquids, whose dynamics result from complex energetic and entropic contributions at the atomic scale. Two scenarios are generally proposed: one represents the dynamics in a fluid as a series of energy-barrier crossings, leading to Arrhenius-like laws, while the other assumes that atoms rearrange themselves by collisions, as exemplified by the free volume model. To assess the validity of these two views, we computed, using molecular dynamics simulations, the transport properties of the Lennard-Jones fluid and tested to what extent the Arrhenius equation and the free volume model describe the temperature dependence of the viscosity and of the diffusion coefficient at fixed pressure. Although both models reproduce the simulation results over a wide range of pressure and temperature covering the liquid and supercritical states of the Lennard-Jones fluid, we found that the parameters of the free volume model can be estimated directly from local structural parameters, also obtained in the simulations. This consistency of the results gives more credibility to the free volume description of transport properties in liquids.

中文翻译：

Lennard-Jones 液体粘度的微观起源

与结晶固体或理想气体不同，液体的传输特性仍然难以从微观角度描述，液体的动力学是由原子尺度上复杂的能量和熵贡献引起的。通常提出两种情况：一种将流体中的动力学表示为一系列能量屏障交叉，导致类似阿累尼乌斯的定律，而另一种假设原子通过碰撞重新排列，如自由体积模型所示。为了评估这两种观点的有效性，我们使用分子动力学模拟计算了 Lennard-Jones 流体的传输特性，并测试了 Arrhenius 方程和自由体积模型在多大程度上描述了粘度和扩散的温度依赖性固定压力下的系数。尽管这两个模型都在涵盖 Lennard-Jones 流体的液态和超临界状态的广泛压力和温度范围内重现了模拟结果，但我们发现自由体积模型的参数可以直接从局部结构参数估计，也可以在模拟。结果的这种一致性为液体中传输特性的自由体积描述提供了更多的可信度。

更新日期：2022-08-11

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11