在超冷液体中,近邻持久性和缓慢异质动态之间的定量关系
Katrianna S Sarkar1, Kevin A Interiano-Alberto1, Jack F Douglas2
1Department of Physics, University of South Florida, Tampa, Florida 33620, USA.
The Journal of chemical physics
|May 19, 2025
概括
玻璃形成液体中的邻居持久性函数 (CB(t)) 遵循双拉伸指数形式,类似于其他放松指标. 它的债券寿命 (τbond) 与α-放松时间 (τα) 相比,在交叉温度 (Tx) 附近达到顶峰,揭示了缓慢动态的洞察力.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 计算化学计算化学
背景情况:
- 形成玻璃的液体在玻璃过渡附近表现出复杂的动态.
- 了解粒子重新排列和持久性对于描述这些动态至关重要.
- 传统的放松指标,如自介散射函数,可以捕捉到这些动态的一些方面.
研究的目的:
- 为了研究玻璃形成液体中正常化的邻居持久性函数,CB(t) 的衰变.
- 为了比较CB(t) 与其他已确定的放松指标.
- 分析与CB (t) 相关的特征时间尺度的温度依赖性及其与异质动态的关系.
主要方法:
- 玻璃形成液体的二元莱纳德-斯模型的分子动力学模拟.
- 对正常化的邻居持久函数CB (t) 衰变的分析.
- 将CB (t) 配合到一个双拉伸指数函数形式.
- 时间尺度的比较:键寿命 (τbond),α放松时间 (τα),重叠时间 (τov) 和不动粒子集群寿命 (τimm).
主要成果:
- CB(t) 衰变在非阿雷尼乌斯体制中遵循双拉伸指数形式,类似于S(q,t).
- 关系tbond/τα表现出非单调的温度依赖,在交叉温度Tx时达到峰值.
- 尽管这些时间尺度存在很大的差异,但tbond仍然与tov相比,敏感性峰值时间tχ仍然与timm相比.
结论:
- 玻璃形成液体的缓慢动态 CB (t) 提供了一种有价值的衡量标准.
- "tbond"和"ta"之间的关系提供了关于玻璃转型附近异质动态的见解.
- CB ((t) 和相关的敏感性 χB ((t) 作为不动粒子集群动态的半定量,空间平均指标.
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