Quantitative Bond Energetics in Atomic-Scale Junctions
Quantitative Bond Energetics in Atomic-Scale Junctions
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DOI：
10.1021/nn502836e
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发表时间：
2014-07-01
期刊：
影响因子：
17.1
通讯作者：
Venkataraman, Latha
中科院分区：
文献类型：
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作者：
Aradhya, Sriharsha V.;Nielsen, Aileen;Venkataraman, Latha
直接测量表征复杂材料中单个化学键的势能面对许多学科都具有重要意义。在这里，我们证明了金属单原子接触和单分子结的能量分布可以通过拟合在接近平衡状态下进行的环境原子力显微镜测量来映射为物理但简单的功能形式。我们从原子力显微镜数据中提取了由金属键和金属-分子键形成的结的键能，并发现我们的结果与基于密度泛函理论的典型结结构计算非常吻合。此外，对大量连接点的测量可以被压缩成一个单一的、通用的力延伸曲线，从而揭示了控制这些化学键的势面整体形状的惊人程度的相似性。与之前在环境条件下的研究相比，我们的方法大大扩展了从这些测量中提取的定量信息，特别是可以直接分析键能的趋势。
A direct measurement of the potential energy surface that characterizes individual chemical bonds in complex materials has fundamental significance for many disciplines. Here, we demonstrate that the energy profile for metallic single-atom contacts and single-molecule junctions can be mapped by fitting ambient atomic force microscope measurements carried out in the near-equilibrium regime to a physical, but simple, functional form. We extract bond energies for junctions formed through metallic bonds as well as metal-molecule link bonds from atomic force microscope data and find that our results are in excellent quantitative agreement with density functional theory based calculations for exemplary junction structures. Furthermore, measurements from a large number of junctions can be collapsed to a single, universal force extension curve, thus revealing a surprising degree of similarity in the overall shape of the potential surface that governs these chemical bonds. Compared to previous studies under ambient conditions where analysis was confined to trends in rupture force, our approach significantly expands the quantitative information extracted from these measurements, particularly allowing analysis of the trends in bond energy directly.