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

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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.