Picosecond laser system for IR-visible sum-frequency generation study of intermediates of surface reactions.

该项目的建设系统的红外-可见光和频发生（IR-vis SFG）光谱研究的中间物种的表面反应开始于1994年，今年是最后一年。今年的工作是对仪器设置进行最后的润色，并获得整个艺术领域实验和分析程序的先进知识。在仪器方面，我们成功地扩大了调谐范围和频率窄化的红外脉冲源，通过将衍射光栅OPO/OPA产生的近红外光束作为源或DFG产生的红外光束。然而，最后的调整或改进仍在进行中。对用于制备洁净表面的机械手或超高真空室进行了改造，使样品温度低于120 K，并探索了提高信噪比的实验方法，对信号处理进行了改进。通过泵浦-探测方法观察了分子筛表面的振动能弛豫，得到了固体表面能量弛豫的基本认识。

This project of constructing the system for the infrared-visible sum-frequency generation (IR-vis SFG) spectroscopy for the study of intermediate species of surface reactions started in 1994 and this year has been the final year. This year's work was to give final touch to the instrumental setups and to obtain advanced know-hows on the experimental and analytical procedures of the art as a whole. On instrumental aspects, we have succeeded in extending the tuning range and frequency-narrowing of infrared pulse source by incorporating a diffraction grating onto the OPO/OPA generation of near-infrared beam which serves as the source or the DFG production of IR beam. Final adjustment, or improvement, is still under way, however. The manipulator or the UHV chamber, which was constructed for the preparation of clean and well-defined surfaces, was reformed to let the sample piece get to the temperature lower than 120K.The exploration of experimental procedures to get better S/N ratio has been made this year too and several improvements in signal processing were made. Basic understanding of energy relaxation at solid surfaces was attained by the pump-probe observation of vibrational energy relaxation at zeolite surfaces with various adsorbates such as noble gas atoms and water molecules interacting with acidic OH groups of the surfaces.