arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.07883physics.chem-phcond-mat.soft
收藏

过冷水中弹性模型的评估:用TIP4P/2005f力场进行的分子动力学研究

Assessment of elastic models in supercooled water: A molecular dynamics study with the TIP4P/2005f force field

Emmanuel Guillaud, Laurent Joly, Dominique De Ligny, Samy Merabia

摘要:

玻璃形成体表现出粘弹性行为:在实验室时间尺度上,它们在低温下表现得像(玻璃状)固体,在高温下表现得像液体。基于这种观察,弹性模型将长时间过冷动力学与过冷液体的短时间弹性性质联系起来。在目前的工作中,我们评估的剪切粘度和$α$ -松弛时间的过冷水的弹性模型的有效性,使用分子动力学模拟的TIP 4P/2005 f力场在很宽的温度范围内。我们表明,弹性模型提供了一个很好的描述过冷水动力学。对于粘度,观察到两个不同的制度和交叉温度被发现是接近的斯托克斯-爱因斯坦关系开始被违反。我们的模拟表明,只有剪切性能是重要的有效流动活化能的特征。这项研究要求在低温下的水的高频弹性特性的实验测定。

英文摘要:

Glass formers exhibit a viscoelastic behavior: at the laboratory timescale, they behave like (glassy) solids at low temperatures, and like liquids at high temperatures. Based on this observation, elastic models relate the long time supercooled dynamics to short time elastic properties of the supercooled liquid. In the present work, we assess the validity of elastic models for the shear viscosity and the $α$-relaxation time of supercooled water, using molecular dynamics simulations with the TIP4P/2005f force field over a wide range of temperatures. We show that elastic models provide a good description of supercooled water dynamics. For the viscosity, two different regimes are observed and the crossover temperature is found to be close to the one where the Stokes-Einstein relation starts to be violated. Our simulations show that only shear properties are important to characterize the effective flow activation energy. This study calls for experimental determination of the high frequency elastic properties of water at low temperatures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑