Revealing the Angular Symmetry of Chemical Bonds by Atomic Force Microscopy
Revealing the Angular Symmetry of Chemical Bonds by Atomic Force Microscopy
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DOI：
10.1126/science.1219850
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发表时间：
2012-04-27
期刊：
影响因子：
56.9
通讯作者：
Giessibl, Franz J.
中科院分区：
文献类型：
--
作者：
Welker, Joachim;Giessibl, Franz J.
我们用扫描隧道显微镜和原子力显微镜相结合的方法，测量了吸附在铜表面的一氧化碳分子与金属尖端原子之间化学键合力的角度依赖关系。我们提供了力和电流随距离的函数图，揭示了作为尖端和样品方法的强定向化学键的出现。根据尖端原子的取向，力图显示了明显的单极小值、双极小值或三极小值，而隧道电流图显示了所有三种尖端条件下的单极小值。我们介绍了一个成键能的角度相关模型，该模型映射了所有观测到的方向和距离的观测实验数据。
We have measured the angular dependence of chemical bonding forces between a carbon monoxide molecule that is adsorbed to a copper surface and the terminal atom of the metallic tip of a combined scanning tunneling microscope and atomic force microscope. We provide tomographic maps of force and current as a function of distance that revealed the emergence of strongly directional chemical bonds as tip and sample approach. The force maps show pronounced single, dual, or triple minima depending on the orientation of the tip atom, whereas tunneling current maps showed a single minimum for all three tip conditions. We introduce an angular dependent model for the bonding energy that maps the observed experimental data for all observed orientations and distances.