Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
J Chem Phys. 2013 Mar 28;138(12):12A514. doi: 10.1063/1.4770337.
Using molecular dynamics simulation on a glass-forming liquid in three dimensions, we investigate the thermal vibrational motions, the configuration changes caused by stringlike jump motions, and their close correlations. The heterogeneous vibrational motions are visualized in terms of a vibration length Si(t) defined for each particle i. The structure factor for the inhomogeneity of Si(t)(2) is also calculated, which exhibits considerable long wavelength enhancement. By examining the birth times of strings, they are shown to appear collectively and intermittently. We show that particles with larger Si(t) tend to trigger jump motions more frequently at later times than those with smaller Si(t). We also show that the particles with fewer bonds tend to have larger Si(t) and participate more frequently in the stringlike motions.
我们使用三维分子动力学模拟研究了玻璃形成液体的热振动运动、串状跳跃运动引起的构型变化及其密切相关性。通过为每个粒子 i 定义振动长度 Si(t)，可以可视化不均匀的振动运动。还计算了 Si(t)(2)不均匀性的结构因子，其表现出相当大的长波长增强。通过检查串的生成时间，表明它们会集体和间歇地出现。我们表明，具有较大 Si(t)的粒子在以后的时间比具有较小 Si(t)的粒子更频繁地触发跳跃运动。我们还表明，具有较少键的粒子往往具有较大的 Si(t)，并且更频繁地参与串状运动。
