Inagaki Motoharu, Motobayashi Kenta, Ikeda Katsuyoshi
Department of Physical Science and Engineering, Nagoya Institute of Technology , Nagoya 466-8555, Japan.
Frontier Research Institute for Materials Science (FRIMS), Nagoya Institute of Technology , Nagoya 466-8555, Japan.
J Phys Chem Lett. 2017 Sep 7;8(17):4236-4240. doi: 10.1021/acs.jpclett.7b01901. Epub 2017 Aug 24.
Surface-enhanced Raman scattering (SERS) microscopy using nanoparticle-assisted gap-mode plasmon excitation, which enables us to observe an atomically defined planar metal surface, was combined with THz-Raman spectroscopy to observe ultra-low-frequency vibration modes under electrochemical conditions. This combination helps us to gain deeper insights into electrode/electrolyte interfaces via direct observation of extramolecular vibrations including information on intermolecular and substrate/molecule interactions. Electrochemical reductive desorption of benzenethiol derivatives from Au(111) and (100) was monitored to demonstrate the power of this spectroscopy. Structural differences of the monolayers between these surfaces were seen only in the extramolecular vibration modes such as a large-amplitude hinge-bending motion of the phenyl ring. On the Au(111), where hollow-site and bridge-site adsorption coexisted, the electrochemical reductive desorption was preferentially induced at the hollow sites.
利用纳米粒子辅助的间隙模式等离子体激元激发的表面增强拉曼散射（SERS）显微镜，使我们能够观察原子级定义的平面金属表面，将其与太赫兹拉曼光谱相结合，以观察电化学条件下的超低频振动模式。这种结合有助于我们通过直接观察分子外振动，包括分子间和底物/分子相互作用的信息，更深入地了解电极/电解质界面。监测苯硫醇衍生物从Au(111)和(100)上的电化学还原解吸，以证明这种光谱学的威力。这些表面之间单层的结构差异仅在分子外振动模式中可见，例如苯环的大幅度铰链弯曲运动。在同时存在空心位和桥位吸附的Au(111)上，电化学还原解吸优先在空心位诱导。
