机械变形区分了分子结合中的道路径
Zuoti Xie, Ioan Bâldea1, Greg Haugstad
1Theoretische Chemie , Universität Heidelberg , INF 229, D-69120 Heidelberg , Germany.
Journal of the American Chemical Society
|December 12, 2018
概括
分子连接的机械拉伸显示出不同的电子道通道. 伸展性乙醇 (CnT) 的导电率没有变化,而乙烯乙醇 (OPTn) 的导电率显著下降,区分局部和非局部轨道.
科学领域:
- 分子电子
- 凝聚物质物理
- 表面科学
背景情况:
- 对于分子电子学来说,了解电子穿过分子道至关重要.
- 区分局部和非局部轨道是控制分子导电性的关键.
- 机械应变对分子结合的影响尚未完全理解.
研究的目的:
- 研究机械拉伸对分子结合中的电子道路径的影响.
- 在压力下区分西格玛- (σ) 和皮- (π) 结合的分子骨架.
- 建立一种用于区分局部与非局部轨道贡献的道方法.
主要方法:
- 使用自组装单层 (SAM) 的乙醇 (CnT) 和小乙烯基醇 (OPTn) 制造分子连接.
- 机械拉伸SAM以调整电极间的分离在安格斯特罗姆水平.
- 测量分子导电性 (G<子>分子子>) 作为分子长度和应变的函数.
- 理论建模以解释观察到的依赖应变的导电变化.
主要成果:
- 拉伸的乙醇 (C nT) 分子结与未拉伸的结具有相同的导电长度依赖性.
- 与未拉伸的结节相比,拉伸的小烯 (OPT n) 分子结节的导电率在增加的分子长度时降低了10倍.
- 结果的差异归因于应变电子合 (Γ) 和主要道轨道的空间范围.
结论:
- 机械拉伸提供了一个强大的工具来区分通过局部化 (σ-bonded) 和非局部化 (π-bonded) 轨道的道.
- 电子合器的应变灵敏度 (Γ) 在σ-和π-结合系统之间有显著差异.
- 电极间分离的安格斯特罗姆级控制提供了一个探测轨道移位和分子结合中的电子合的策略.
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