It was a long-cherished dream for chemists to take a direct look at chemical bonding, a fundamental component of chemistry. This dream was finally accomplished by the state-of-the-art noncontact atomic force microscopy (NC-AFM) equipped with qPlus force sensors and carbon monoxide (CO) functionalized tips. The resolved interconnectivity between atoms and molecules in NC-AFM frequency shift images is interpreted as chemical bonding, providing essential knowledge of the bond length, bond angle and even bond order. The featured contrast of different chemical bonds can serve as fingerprints for further interpretation of chemical structures toward unknown species synthesized on surfaces. This breakthrough enriches characterization tools for surface science and brings our understanding of on-surface reactions to a new level. Beyond bond imaging, the application of NC-AFM has been extended to quantifying interatomic interactions, identifying three-dimensional nanostructures, manipulating molecules and reactions, as well as determining molecular electronic characteristics. Moreover, some recent efforts address the improvement of the usability and versatility of the bond-resolved NC-AFM technique, including high-resolution molecular investigation on bulk insulators, application-specific tip modification, stable bond imaging above liquid helium temperature and autonomous experimentation implemented by artificial intelligence.

对于化学家而言，直接了解化学键是化学的基本组成部分是一个梦dream以求的梦想。最终，这个梦想通过配备qPlus力传感器和一氧化碳（CO）功能化尖端的最新非接触原子力显微镜（NC-AFM）得以实现。NC-AFM频移图像中原子与分子之间已解决的互连性被解释为化学键合，从而提供了键长，键角甚至键序的基本知识。不同化学键的特征对比可以用作指纹，以进一步解释表面上合成的未知物种的化学结构。这一突破丰富了表面科学的表征工具，使我们对表面反应的理解达到了一个新的水平。除了键合成像之外，NC-AFM的应用已扩展到量化原子间相互作用，识别三维纳米结构，操纵分子和反应以及确定分子电子特性。此外，最近的一些工作致力于解决键分解的NC-AFM技术的可用性和多功能性的改进，包括对大体积绝缘子的高分辨率分子研究，特定用途的尖端修饰，液氦温度以上的稳定键成像以及实施的自主实验。通过人工智能。