Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Phys Rev Lett. 2012 Jun 1;108(22):225506. doi: 10.1103/PhysRevLett.108.225506.
It has been demonstrated recently that supercooled liquids sharing simple structural features (e.g. pair distribution functions) may exhibit strikingly distinct dynamical behavior. Here we show that a more subtle structural feature correlates with relaxation times in three simulated systems that have nearly identical radial distribution functions but starkly different dynamical behavior. In particular, for the first time we determine the thermodynamic "point-to-set" length scale in several canonical model systems and demonstrate the quantitative connection between this length scale and the growth of relaxation times. Our results provide clues necessary for distinguishing competing theories of the glass transition.
最近已经证明,具有简单结构特征(例如,配分函数)的过冷液体可能表现出显著不同的动力学行为。在这里,我们展示了一个更微妙的结构特征与三个模拟系统中的弛豫时间相关,这三个模拟系统具有几乎相同的径向分布函数,但动力学行为却截然不同。特别是,我们首次在几个典型模型系统中确定了热力学“点到集合”长度尺度,并证明了这个长度尺度与弛豫时间增长之间的定量关系。我们的结果为区分玻璃化转变的竞争理论提供了必要的线索。