Observation of Adsorbed Species at an Electrode/Solution Interface by Magneto-Optical Rotation

本研究的目的是建立一种新的分析方法来观察磁场下电极/溶液界面上的吸附物质。本研究的一个特点是原位观察磁场对吸附剂光学性质的影响。1985年研制了电极/溶液界面磁光旋转光谱仪。仪器由1个磁铁和样品架、2个偏光片和分析仪、3个光电倍增管、4个细胞室、5个灯、6个恒电位器和函数发生器组成。为此，还制作了碳布的光学透明薄层电极（OTTLE）。1986年，利用该装置获得了<NiSO_4>、<CoCl_2>和氯丙嗪溶液电解过程中碳布电极/溶液界面上化学物质的磁光光谱。在<NiSO_4>或<CoCl_2>溶液的电解过程中，观察到碳布OTTLE随磁场和电极电位的旋光性。氯丙嗪在0.6V时氧化生成氯丙嗪阳离子自由基。自由基的旋光度强烈地依赖于磁场的强度。该方法不仅可用于检测电极/溶液界面上的吸附物质，还可用于检测电极反应的中间体，如有机自由基。

The objective of this research is to make a new analytical method for observation of adsorbed species at an electrode/solution interface under magnetic field. A characteristic of this research is to observe in situ the changes in optical properties of adsorbates caused by magnetic field.An apparatus for magneto-optical rotation spectroscopy of the electrode/ solution interface was prepared in 1985. The apparatus was constituted of 1 magnet and sample holder, 2 polarizer and analyzer, 3 photomultiplier, 4 cell compartment, 5 lamp, 6 potentiostat and function generator. Optically transparent thin layer electrode(OTTLE) of carbon cloth was also made for this research.In 1986, the apparatus was used to obtain the magneto-optical spectra of chemical species at the carbon cloth electrode/solution interface during electrolysis of a <NiSO_4> , a <CoCl_2> or a chlorpromazine solution. Optical rotation of carbon cloth OTTLE was observed depending on the magnetic field and the electrode potential during electrolysis of a <NiSO_4> or a <CoCl_2> solution. At 0.6V chlorpromazine was oxidized to produce chlorpromazine cation radical. Optical rotation of the radical is strongly dependent on the strength of the magnetic field.The method is useful in detecting not only adsorbed species at the electrode/ solution interface but also electrode reaction intermediates such as organic radicals.