Guo Jing, You Sifan, Wang Zhichang, Peng Jinbo, Ma Runze, Jiang Ying
International Center for Quantum Materials, School of Physics, Peking University.
International Center for Quantum Materials, School of Physics, Peking University; Collaborative Innovation Center of Quantum Matter;
J Vis Exp. 2018 May 27(135):57193. doi: 10.3791/57193.
Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal structure and probing the hydrogen-bond (H-bond) dynamics of the water molecules adsorbed on solid surfaces are fundamental issues of water science, which remains a great challenge owing to the light mass and small size of hydrogen. Scanning tunneling microscopy (STM) is a promising tool for attacking these problems, thanks to its capabilities of sub-Ångström spatial resolution, single-bond vibrational sensitivity, and atomic/molecular manipulation. The designed experimental system consists of a Cl-terminated tip and a sample fabricated by dosing water molecules in situ onto the Au(111)-supported NaCl(001) surfaces. The insulating NaCl films electronically decouple the water from the metal substrates, so the intrinsic frontier orbitals of water molecules are preserved. The Cl-tip facilitates the manipulation of the single water molecules, as well as gating the orbitals of water to the proximity of Fermi level (EF) via tip-water coupling. This paper outlines the detailed methods of submolecular resolution imaging, molecular/atomic manipulation, and single-bond vibrational spectroscopy of interfacial water. These studies open up a new route for investigating the H-bonded systems at the atomic scale.
水/固界面无处不在，在许多环境、生物物理和技术过程中发挥着关键作用。解析吸附在固体表面的水分子的内部结构并探测其氢键（H键）动力学是水科学的基本问题，由于氢的质量轻、尺寸小，这仍然是一个巨大的挑战。扫描隧道显微镜（STM）是解决这些问题的一种很有前景的工具，这得益于其亚埃级的空间分辨率、单键振动灵敏度以及原子/分子操纵能力。所设计的实验系统由一个Cl端接的针尖和一个通过在Au(111)支撑的NaCl(001)表面原位注入水分子制备的样品组成。绝缘的NaCl薄膜使水与金属基底在电子上解耦，因此水分子的本征前沿轨道得以保留。Cl针尖有助于对单个水分子进行操纵，以及通过针尖-水耦合将水的轨道选通到费米能级（EF）附近。本文概述了界面水的亚分子分辨率成像、分子/原子操纵和单键振动光谱的详细方法。这些研究为在原子尺度上研究氢键系统开辟了一条新途径。
