原子分子动力学化学力显微镜模拟的原子分子动力学
David L Patrick1, John F Flanagan, Patrick Kohl
1Department of Chemistry, Western Washington University, 516 High Street, Bellingham, WA 98225, USA. patrick@chem.wwu.edu
Journal of the American Chemical Society
|May 29, 2003
概括
原子模拟揭示了化学力显微镜的尖端样品相互作用在负载下如何变化. 自组装的单层薄膜固化,其组成发生变化,力分布不均,偏离标准接触力学模型.
科学领域:
- 表面科学是一门学科.
- 纳米技术 纳米技术
- 计算化学计算化学
背景情况:
- 化学力显微镜 (CFM) 探测分子级粘附和三角学.
- 解释CFM需要理解不可观察的尖端样本结合过程.
- 原子运动和力分布是关键的,但在实验中无法获得的细节.
研究的目的:
- 模拟CFM尖端与固体墙相互作用的原子分子动力学.
- 为了研究C12基酸盐自组装单层 (SAM) 在装卸过程中的行为.
- 将模拟结果与已建立的接触力学模型进行比较.
主要方法:
- 原子学分子动力学模拟.
- 用C12基酸盐SAM与固体墙体接触的CFM笔进行建模.
- 在近平衡条件下模拟完整的装载-卸载序列.
主要成果:
- 在压缩时,SAM膜从流体转变为固态.
- 接触组合在加载过程中发生变化,暴露了薄膜的内部.
- 接触处的力分布不均,局部波动很大.
- 标准模型 (JKR,DMT,赫兹) 显示与模拟数据的偏差.
结论:
- 分子动力学模拟提供了关于CFM尖端样本交叉点动态的见解.
- 由于未观察到的现象和模型的局限性,实验解释可能存在缺陷.
- 需要改进的模型,考虑有限厚度和非线性弹性.
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