INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000 Bahía Blanca, Argentina.
J Phys Chem B. 2023 Apr 20;127(15):3516-3523. doi: 10.1021/acs.jpcb.2c08583. Epub 2023 Apr 6.
To become a glass from the metastable supercooled state, a liquid experiences a dramatic dynamical slowing down within a narrow temperature window. However, the attainment of solid rigidity is not the result of breaking translational symmetry as in a crystal: the structure of the resulting amorphous solid strikingly resembles that of the liquid state. Moreover, the supercooled liquid is dynamically heterogeneous; that is, the dynamics varies by orders of magnitude from one region of the sample to another, but the establishment of the existence of strong structural differences between such regions has demanded hard efforts along the years. In this work, we focus precisely on such a structure-dynamics link for supercooled water showing that local regions with structural defectiveness are persistent during the structural relaxation of the system, hence acting as early time predictors of later intermittent glassy relaxation events.
为了从亚稳过冷状态变成玻璃，液体需要在很窄的温度窗口内经历剧烈的动力学减速。然而，获得固体刚性并不是像在晶体中那样打破平移对称性的结果：所得无定形固体的结构惊人地类似于液体状态。此外，过冷液体在动力学上是不均匀的；也就是说，动力学在样品的一个区域到另一个区域之间相差几个数量级，但多年来一直努力证明这些区域之间存在强烈的结构差异。在这项工作中，我们正是关注过冷水中的这种结构-动力学关系，表明具有结构缺陷的局部区域在系统的结构弛豫过程中是持续存在的，因此它们是后续间歇性玻璃化弛豫事件的早期时间预测因子。
