Evidence for the weak steric hindrance scenario in the supercooled-state reorientational dynamics
Evidence for the weak steric hindrance scenario in the supercooled-state reorientational dynamics
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DOI：
10.1103/physrevlett.94.215701
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发表时间：
2005-06-03
影响因子：
8.6
通讯作者：
Kob, W
中科院分区：
文献类型：
--
作者：
Chong, SH;Moreno, AJ;Kob, W
我们使用分子动力学计算机模拟来研究哑铃玻璃形成液体的平移和重定向动力学。对于足够长的分子，发现了旋转动力学的标准强位阻情形。然而，对于小延伸，我们发现了一个不同的场景-弱位阻场景-由一种新型的玻璃化转变引起的，其中分子轴的取向动力学随着非遍历性参数的不断增加而发生动态转变。这些结果与模式耦合理论对玻璃化转变的理论预测一致。
We use molecular-dynamics computer simulations to study the translational and reorientational dynamics of a glass-forming liquid of dumbbells. For sufficiently elongated molecules the standard strong steric hindrance scenario for the rotational dynamics is found. However, for small elongations we find a different scenario-the weak steric hindrance scenario-caused by a new type of glass transition in which the orientational dynamics of the molecule's axis undergoes a dynamical transition with a continuous increase of the nonergodicity parameter. These results are in agreement with the theoretical predictions by the mode-coupling theory for the glass transition.