First-principle determination of landscape and the unifying concept for glass transition

景观的第一性原理确定与玻璃化转变的统一概念

基本信息

批准号：
15340139
负责人：
ODAGAKI Takashi
金额：
$ 9.54万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340139/
关键词：
Glass transition Free energy landscape Density functional theory String motion Second order complex specific heat Principal component analysis Cooperatively rearranging region Voronoi tessellation 散逸系の境界摂動粒子分散系 AC比熱低エネルギー励起ソリトンの

项目摘要

1.A unifying concept for understanding glass transition was found on the basis of the free energy landscape which plays the same role as the free energy in the Landau theory of phase transitions.2.A novel method to calculate the free energy landscape was found using the density functional of the grand potential. Analyzing the free energy landscape obtained, we showed that the string motion is a common elementary process of the slow relaxation and that there are two kinds of the cooperatively rearranging regions.3.The principal component analysis was utilized to calculate the free energy landscape from the molecular simulation data.4.An interactive molecular dynamics simulation and a fast method to construct the Voronoi tessellation were developed. These methods were exploited to calculate the temperature dependence of the cooperatively rearranging region.5.Using a microscopic theory we showed that the jump rate distribution obeys a power law function.6.The temperature dependence of the specific heat of a model glass former was obtained within the frame work of the free energy landscape and it was shown that the cooling rate dependence of the glass transition can be explained by the landscape picture.7.On the basis of the free energy landscape picture, the first and second order frequency-dependent (complex) specific heats were defined and their anomalous behavior was found around the glass transition point and the Vogel-Fulcher temperature.8.Packing fraction of binary hard discs was obtained in the entire parameter space and it was found that the packing fraction has a minimum as a function of the ratio of radii.

1.在自由能景观的基础上找到了理解玻璃化转变的统一概念，它与朗道相变理论中的自由能具有相同的作用。2.找到了一种计算自由能景观的新方法大势的密度泛函。通过对得到的自由能图谱的分析，我们发现弦运动是慢弛豫的常见基本过程，并且存在两种协同重排区域。3.利用主成分分析法计算自由能图谱。 4.开发了交互式分子动力学模拟和快速构建Voronoi曲面细分的方法。利用这些方法来计算协同重排区域的温度依赖性。5.利用微观理论，我们表明跳跃率分布服从幂律函数。6.获得了模型玻璃成型体的比热的温度依赖性在自由能景观的框架内，表明玻璃化转变的冷却速率依赖性可以通过景观图来解释。7.在自由能景观图的基础上，一阶和二阶频率相关（复）比热被定义并在玻璃化转变点和 Vogel-Fulcher 温度附近发现了它们的反常行为。 8.在整个参数空间内获得了二进制硬盘的堆积分数，发现堆积分数作为比率的函数具有最小值半径。