Tests of an approximate scaling principle for dynamics of classical fluids.
Tests of an approximate scaling principle for dynamics of classical fluids.
复制标题
经典流体动力学近似标度原理的测试。
DOI：
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发表时间：
2005
影响因子：
3.3
通讯作者：
H. C. Andersen
中科院分区：
文献类型：
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作者：
T. Young;H. C. Andersen
我们使用分子动力学计算机模拟来测试一个近似缩放原理，该原理猜想，如果正确调整两个液体的长度尺度时，即使对两个液体的长度尺度具有相同的密度和相似的静态对相关函数，则两个平衡原子液具有非常相似的动力学特性。它们具有不同的原子间潜力和不同的温度。在相同密度的各种温度下，对两种模型原子液体进行了模拟。在第一种类型中，原子间电位是Lennard-Jones电位（LJ）。在第二种类型中，原子间电位是Lennard-Jones电位（RLJ）的排斥部分。我们确定了具有非常相似的对相关函数的系统对，尽管它们具有不同的潜力。每对由特定温度下的LJ液体和在较低温度下的相应RLJ液体组成。我们比较了每对两个系统的各种时间相关函数和传输系数。根据近似缩放原则，每对的动力学特性在每对中都非常相似，而其他动力学特性则显着不同。结果表明，某些动力学特性对原子间电位的巨大变化非常不敏感，这些变化使对函数的变化在很大程度上没有变化，而其他动力学属性对潜在的这种变化更为敏感。扩散和粘度的传输系数是对电势变化不敏感的动力学特性之一，这可能是根据简单的液体模型计算或合理化了许多流体运输特性的原因的一部分。
We used molecular dynamics computer simulations to test an approximate scaling principle that conjectures that two equilibrium atomic liquids have very similar dynamical properties if they have the same density and similar static pair correlation functions when the length scales of the two liquids are adjusted appropriately, even if they have different interatomic potentials and different temperatures. The simulations were performed on two types of model atomic liquids at various temperatures at the same density. In the first type, the interatomic potential is the Lennard-Jones potential (LJ). In the second type, the interatomic potential is the repulsive part of the Lennard-Jones potential (RLJ). We identified pairs of systems that have very similar pair correlation functions despite the fact that they had different potentials. Each pair consisted of an LJ liquid at a specific temperature and a corresponding RLJ liquid at a lower temperature. We compared various time correlation functions and transport coefficients of the two systems in each pair. Many dynamical properties are very similar in each pair, in accordance with the approximate scaling principle, whereas others are significantly different. The results indicate that certain dynamical properties are very insensitive to large changes in the interatomic potential that leave the pair correlation function largely unchanged, whereas other dynamical properties are much more sensitive to such changes in the potential. The transport coefficients for diffusion and viscosity are among the dynamical properties that are insensitive to such changes in the potential, and this may be part of the reason transport properties of many fluids have been calculated or rationalized in terms of a simple hard sphere model of liquids.