Theoretical Study of Glass Transition and Slow Dynamics

玻璃化转变和慢动力学的理论研究

基本信息

批准号：
06640509
负责人：
ODAGAKI Takashi
金额：
$ 1.47万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06640509/
关键词：
glass transition slow relaxation and fast process ideal three mode model trapping diffusion model non-gaussianity molecular dynamics simulation Vogel-Fulcher law alpha-and beta-relaxation 遅い緩和速い過程ノンガウシアニティー二成分ソフトスフェア-系 Vogel-Ful

项目摘要

The main theme of the present research project is to understand the dynamical properties of vitrification process in a unified manner and to elucidate the physics of the glass forming process. We studied the trapping diffusion model (TDM) more throughly and gave the theoretical foundation of the model. We also performed a molecular dynamics simulation to find out the changes in dynamical properties of supercooled liquids.We extended the TDM to include the trapped motion as well as the non-trapped jump motion and obtained the dynamical structure factor. We showed that the main relaxation time obeys the Vogel-Fulcher law and obtained the non-Gaussianity which agees qualitatively with experiments.We also devised a new technique (log-Cole-Cole analysis) with which we can find easily the nature of the relaxation.The extensive MD simulation was carried out for a binary soft shpere system covering the liquid state, supercooled liquid state and glassy state. We found the Vogel-Fulcher law for the main relaxation time, Boson-peak and the fast process.We proposed an ideal three model mode consisting of an oscillation and two kinds of stochastic motions and showed that this model can reproduce the dynamical charasteristics of supercooled liquids.The foundation of the TDM was discussed extensively and it was shown that similar dynamics would be commonly observed in systems with activation processes with randam activation energies. We also showed that the divergence of various moments signifies the dynamical transitions and that the difference of temerature multiplied by the excess entropy from its value the glass transition point can serve as the scaling parameter for the transition.

本研究项目的主题是以统一的方式了解玻璃化过程的动力学特性，并阐明玻璃形成过程的物理。我们更透彻地研究了捕获扩散模型（TDM），并给出了模型的理论基础。我们还进行了一个分子动力学模拟，以找出超冷液体动力学特性的变化。我们将TDM扩展到包括捕获的运动以及未捕获的跳跃运动并获得了动态结构因子。 We showed that the main relaxation time obeys the Vogel-Fulcher law and obtained the non-Gaussianity which agees qualitatively with experiments.We also devised a new technique (log-Cole-Cole analysis) with which we can find easily the nature of the relaxation.The extensive MD simulation was carried out for a binary soft shpere system covering the liquid state, supercooled liquid state and glassy state.我们在主要放松时间，玻孔峰和快速过程中找到了Vogel-Fulcher定律。我们提出了一种理想的三种模式模式，该模式由振荡和两种随机运动组成，并表明该模型可以重现超冷的动态性charstelmistications and Supercored液体的动态性，并与TDM的基础进行了类似的激活。能量。我们还表明，各种力矩的差异表示动态跃迁，而诱变的差异乘以过量熵与其值的过度熵乘以玻璃过渡点可以作为过渡的缩放参数。