Peng Jinbo, Guo Jing, Hapala Prokop, Cao Duanyun, Ma Runze, Cheng Bowei, Xu Limei, Ondráček Martin, Jelínek Pavel, Wang Enge, Jiang Ying
International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China.
Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic.
Nat Commun. 2018 Jan 9;9(1):122. doi: 10.1038/s41467-017-02635-5.
Scanning probe microscopy has been extensively applied to probe interfacial water in many interdisciplinary fields but the disturbance of the probes on the hydrogen-bonding structure of water has remained an intractable problem. Here, we report submolecular-resolution imaging of the water clusters on a NaCl(001) surface within the nearly noninvasive region by a qPlus-based noncontact atomic force microscopy. Comparison with theoretical simulations reveals that the key lies in probing the weak high-order electrostatic force between the quadrupole-like CO-terminated tip and the polar water molecules at large tip-water distances. This interaction allows the imaging and structural determination of the weakly bonded water clusters and even of their metastable states with negligible disturbance. This work may open an avenue for studying the intrinsic structure and dynamics of ice or water on surfaces, ion hydration, and biological water with atomic precision.
扫描探针显微镜已在许多跨学科领域中广泛应用于探测界面水，但探针对水的氢键结构的干扰一直是个棘手的问题。在此，我们报告了通过基于qPlus的非接触原子力显微镜在几乎非侵入性区域内对NaCl(001)表面水团簇进行的亚分子分辨率成像。与理论模拟的比较表明，关键在于在较大的针尖-水距离下探测类四极杆CO端接针尖与极性水分子之间微弱的高阶静电力。这种相互作用使得能够对弱键合水团簇甚至其亚稳态进行成像和结构测定，且干扰可忽略不计。这项工作可能为以原子精度研究表面冰或水的内在结构和动力学、离子水合作用以及生物水开辟一条途径。
