论文标题
原子运动在液体固体过渡时的普遍特征
Universal Character of Atomic Motions at the Liquid-Solid Transition
论文作者
论文摘要
我们从计算机模拟中展示了有关简单液体原子动力学中普遍特征的证据，这些特征是预示着冻结过渡的原子动力学。我们开发了一个物理透明的模型，以阐明负责预耐效应的物理学。我们发现，冰点与两个特征时间尺度的交叉相伴随，即液体构型的平均振荡时间在势能表面的最低最小值中，以及由于粒子连续的动态重排而导致势能微小的平均时间分离。当进入过冷机制时，运输时间会小于振荡周期，并且热搅动的无序效应与相互作用的订购效应之间的微妙平衡可能会不稳定，而不利于周期性的顺序。最后，我们证明了发现的前寿命特征产生了一种新的有效方法，用于确定原子模拟的真实材料的液体固体共存线，这与材料科学中常用的其他方法不同，不需要知道固相结构。
We show evidence from computer simulations of a universal feature in the atoms dynamics of simple liquids that heralds the freezing transition. We develop a physically transparent model to shed light on the physics responsible for the precursory effect. We find that the freezing point is concomitant with the crossover of two characteristic time scales, namely the average period of oscillation of the liquid configuration in a minimum of the potential energy surface, and the average time separating transits between potential energy minima as a result of the continuous dynamical rearrangement of particles. When entering the undercooled regime, the transit time becomes smaller than the period of oscillation, and the delicate balance between the disordering effects of thermal agitation and the ordering effects of interactions can be destabilized in favor of the periodic order. Finally, we demonstrate that the discovered precursory feature gives rise to a new efficient method for determining the liquid-solid coexistence line of real materials from atomistic simulations, which, unlike other methods commonly used in materials science, does not require knowing the crystalline structure of the solid phase.
