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arXiv 2009.14718cond-mat.stat-mechcond-mat.soft
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液-固相变时原子运动的普适性

Universal Character of Atomic Motions at the Liquid-Solid Transition

Jerome Daligault

摘要:

我们从计算机模拟的一个普遍的功能,预示着冻结过渡的简单液体的原子动力学的证据。我们开发了一个物理上透明的模型,以阐明物理上负责的寄生效应。我们发现凝固点是伴随着两个特征时间尺度的交叉,即液体组态在势能面极小值处的平均振荡周期,以及作为粒子连续动力学重排结果的势能极小值之间的平均间隔时间。当进入过冷状态时,过渡时间变得小于振荡周期,并且热搅动的无序效应和相互作用的有序效应之间的微妙平衡可以不稳定,有利于周期性秩序。最后,我们证明了所发现的特征产生了一种新的有效的方法,用于确定从原子模拟的实际材料的液-固共存线,这与材料科学中常用的其他方法不同,不需要知道固相的晶体结构。

英文摘要:

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.

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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