Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871, Japan.
Nat Commun. 2017 Apr 26;8:15155. doi: 10.1038/ncomms15155.
Electronegativity is a fundamental concept in chemistry. Despite its importance, the experimental determination has been limited only to ensemble-averaged techniques. Here, we report a methodology to evaluate the electronegativity of individual surface atoms by atomic force microscopy. By measuring bond energies on the surface atoms using different tips, we find characteristic linear relations between the bond energies of different chemical species. We show that the linear relation can be rationalized by Pauling's equation for polar covalent bonds. This opens the possibility to characterize the electronegativity of individual surface atoms. Moreover, we demonstrate that the method is sensitive to variation of the electronegativity of given atomic species on a surface due to different chemical environments. Our findings open up ways of analysing surface chemical reactivity at the atomic scale.
电负性是化学中的一个基本概念。尽管它很重要，但实验测定仅限于总体平均技术。在这里，我们报告了一种通过原子力显微镜评估单个表面原子电负性的方法。通过使用不同的针尖测量表面原子上的键能，我们发现不同化学物质的键能之间存在特征线性关系。我们表明，这种线性关系可以用Pauling 方程对极性共价键进行合理化。这为表征单个表面原子的电负性开辟了可能性。此外，我们证明该方法对由于不同化学环境导致表面上给定原子种类的电负性变化敏感。我们的发现为在原子尺度上分析表面化学反应性开辟了途径。
