大量液体水中的高温动态行为:使用OPC和TIP4P-Ew潜力的分子动力学模拟研究
Andrea Gabrieli1, Marco Sant1, Saeed Izadi2
1Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via Vienna 2, 07100 Sassari, Italy.
概括
分子动力学模拟揭示了水的温度依赖交叉行为,影响键和扩散. 这种交叉发生在生物相关温度附近,这表明对生物分子系统的影响.
科学领域:
- 计算物理和化学 计算物理和化学
- 软物质物理学 软物质物理学
- 生物物理学的生物物理.
背景情况:
- 了解散装水的动态行为至关重要,特别是在300K以上的温度下.
- 关键性质包括扩散系数,键动态和最近邻居的寿命.
- 之前的实验研究发现了水的动态性质中具有特征的交叉温度 (T*).
研究的目的:
- 通过使用经典分子动力学模拟来研究散装水的高温动态行为.
- 为了比较最佳点电荷 (OPC) 和TIP4P-Ew水模型在复制实验观测中的性能.
- 分析扩散的温度依赖性,结合,以及在交叉温度 (T*) 周围的近邻相互作用.
主要方法:
- 经典的分子动力学模拟对散装水进行.
- 我们使用了两个水潜力,OPC和TIP4P-Ew,并进行了比较.
- 分析包括扩散系数和旋转放松,热膨胀和键/最近邻居寿命的阿雷尼乌斯图.
主要成果:
- 在OPC和TIP4P-Ew模型中观察到温度诱导的水动态交叉,与实验T*值 (约315K) 一致.
- 模拟准确地复制了实验交叉在热膨胀系数.
- 发现键和近邻生命周期在T*附近交叉,键在T*以下占主导地位,而简单的液体行为在T*以上出现.
结论:
- 无论是OPC和TIP4P-Ew模型都捕捉到了水动态的基本交叉行为.
- 识别的交叉温度 (T*) 表示水的结构主导性从键转变为简单的类似液体的相互作用.
- 由于T*与生物相关温度的距离很近,因此需要进一步研究其对生物分子系统的影响.
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