Synchrotron-Radiation Electron-Spectroscopy for Chemical Analysis on molecules in solution

本研究是对液体中内壳层激发超激发分子光谱学的综合发展，是超激发分子动力学概念的延伸，是原子物理与生物系统之间不同观点的桥梁。研究的目的是证实分子在溶液中的移动的性质及其被氢键水网络包围的优先结构。为了获得上述性质的实时和原位信息，开发了一种使用高亮度单色X射线同步辐射的液体样品化学分析的电子能谱。采用液体分子束技术在高真空条件下制备液体样品，并在SPring 8装置BL-23 SU束线上设计、建造了一台配备液体分子束源的光电子能谱仪。谱仪的控制/数据采集系统也是新建成的。通过软X射线同步辐射激发和高能电子束轰击实验，对谱仪进行了优化。为了实现液体分子束的稳定产生，已经开发了各种技术。利用该装置，我们首次成功地观测到了液态水在氧K边附近的X射线吸收近边结构（XANES），通过测量光电子总产额，揭示了液态水的电子结构和能量结构。2004年5月25日至30日在加拿大班夫举行的第八届DNA损伤国际研讨会上将应邀介绍这一结果。

The present investigation is a synthetic development of the new spectroscopy for the inner-shell-excited superexcited molecules playing a significant role in the radiation damage and its restoration in liquid, which is the extension of the concept of the dynamics of superexcited molecules and the bridging of different viewpoints between the atomic physics and bio-systems. The purpose of the investigation is to substantiate the mobile properties of molecules and their preferential structure surrounded by hydrogen-bonded water network in solution. To obtain the real-time and in situ information for the above properties, an electron spectroscopy for chemical analysis on a liquid sample using high-brilliance monochromatic X-ray synchrotron radiation is developed. The liquid sample is prepared under a high vacuum using a liquid molecular beam technique.A photoelectron spectrometer equipped with a liquid molecular beam source has newly been designed, constructed, and installed at the beam-line BL-23SU in the SPring8 facility. The control/data-acquisition system for the spectrometer mas also been newly constructed. The spectrometer has been optimized by the experiments both by the soft-X-ray synchrotron radiation excitation and the energetic electron beam bombardment. To achieve a stable production of the liquid molecular beam, various techniques have been developed. The entitled new apparatus has, thus, been established.Using the new apparatus, we have been successful in the first observation of X-ray absorption near edge structure (XANES) for liquid water in the vicinity of oxygen K-edge by measuring the total photoelectron yields, revealing the electronic and energetic structures of water in liquid. An invited presentation of the result will be given in the 8th International Workshop on DNA Damage, May 25-30, 2004 in Banff, Canada.