Structure and Dynamics of the Quasi-Liquid Layer at the Surface of Ice from Molecular Simulations
Structure and Dynamics of the Quasi-Liquid Layer at the Surface of Ice from Molecular Simulations
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DOI：
10.1021/acs.jpcc.8b07724
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发表时间：
2018-11-01
影响因子：
3.7
通讯作者：
Donadio, Davide
中科院分区：
文献类型：
--
作者：
Kling, Tanja;Kling, Felix;Donadio, Davide
采用分子动力学模拟方法，采用自洽水模型，研究了冰表面准液体层的结构和动力学性质。我们的模拟结果表明，对于三个低指数冰面，只有最外层的分子层呈现短程和中程无序，是扩散。正常扩散的起始温度远高于过冷水的玻璃化温度，虽然QLL的扩散率高于相应温度下的散装水。下面的次表层施加一个有序的模板，这产生了一个规则的图案的冰/水界面在任何温度下，是负责QLL和散装水之间的主要差异，特别是对于什么关注的动态和中程结构的氢键网络。我们的工作强调了需要一个整体的方法来表征QLL，作为一个单一的实验技术可能只探测一个特定的功能，错过了这个迷人的系统的复杂性的一部分。
We characterized the structural and dynamical properties of the quasi-liquid layer (QLL) at the surface of ice by molecular dynamics simulations with a thermodynamically consistent water model. Our simulations show that for three low-index ice surfaces, only the outermost molecular layer presents short-range and midrange disorder and is diffusive. The onset temperature for normal diffusion is much higher than the glass temperature of supercooled water, although the diffusivity of the QLL is higher than that of bulk water at the corresponding temperature. The underlying subsurface layers impose an ordered template, which produces a regular patterning of the ice/water interface at any temperature and is responsible for the major differences between QLL and bulk water, especially for what concerns the dynamics and the midrange structure of the hydrogen-bonded network. Our work highlights the need for a holistic approach to the characterization of QLL, as a single experimental technique may probe only one specific feature, missing part of the complexity of this fascinating system.