论文标题
非对称浴缸模型的液体和塑料晶体阶段的同构不变性
Isomorph invariance in the liquid and plastic-crystal phases of asymmetric-dumbbell models
论文作者
论文摘要
我们介绍了由``分子''组成的非对称哑铃模型的数值研究，该模型由``分子''构建为两个由刚性键连接的不同尺寸的Lennard-Jones球体。就最大（a）粒子半径而言，我们报告了键长的0.05、0.1、0.2和0.5的液相的结构和动力学数据，以及键晶相的类似数据的键长度为0.05、0.1、0.2和0.3。通过AA，AB和BB径向分布函数探测结构。通过A和B粒子平均位移作为时间的函数和旋转时间自动相关函数探测动力学。与系统强大的病毒电位能量相关性一致，发现结构和动力学是同构的不变性，即减少单元中良好的近似值，而它们通常沿着相同（20％）密度变化的等温线差异很大。即使是由于恒定键长的旋转时间自动相关函数，也不会预计异构键不变，沿等速异构的变化更大。我们的发现提供了对塑料晶体的同构理论预测的首次验证，实际上，同构的不变性比在不对称 - 倾斜模型的液相中应用更好。
We present a numerical study of the asymmetric dumbbell model consisting of ``molecules'' constructed as two different-sized Lennard-Jones spheres connected by a rigid bond. In terms of the largest (A) particle radius, we report data for the structure and dynamics of the liquid phase for the bond lengths 0.05, 0.1, 0.2, and 0.5, and analogous data for the plastic-crystal phase for the bond lengths 0.05, 0.1, 0.2, and 0.3. Structure is probed by means of the AA, AB, and BB radial distribution functions. Dynamics is probed via the A and B particle mean-square displacement as functions of time and via the rotational time-autocorrelation function. Consistent with the systems' strong virial potential-energy correlations, the structure and dynamics are found to be isomorph invariant to a good approximation in reduced units, while they generally vary considerably along isotherms of the same (20%) density variation. Even the rotational time-autocorrelation function, which due to the constant bond length is not predicted to be isomorph invariant, varies more along isotherms than along isomorphs. Our findings provide the first validation of isomorph-theory predictions for plastic crystals for which isomorph invariance, in fact, is found to apply better than in the liquid phase of asymmetric-dumbbell models.
