New Spectroscopy using combination of synchrotron radiation and laser

为了研究光致相变，近年来我们发展了同步辐射和激光相结合的新技术。(1)我们已经在KEK-PF的XAFS站建立了新的快速数据采集系统，在那里可以使用来自摇摆器的强X射线。由于XAFS能提供组分间的原子距离，因此该系统可用于研究光致结构变化。将该体系应用于自旋交叉配合物，得到了光诱导相晶体结构的新信息。(2)我们还在分子科学研究所建立了基于同步辐射和激光的组合光电子系统。在束线BL 5A和BL 6A 2处，进行了芯能级光电子能谱研究GaAs的光生表面光电压。[Fe（2-pic）_3] Cl_2EtOH单晶的光致相变用同步辐射光电子能谱和激光光电子能谱研究。在室温下，Fe（2-pic）_3] Cl_2EtOH的UPS光谱没有显示出任何变化，但在室温下冷却到40 K以及在40 K下激光激发时，其价态发生了剧烈的变化。实验结果表明，光生相的电子结构不同于高自旋态。(3)在京都大学生长了自旋交叉配合物的单晶，并建立了ESR和拉曼系统来研究光诱导相变。拉曼光谱的结果表明，[Fe（2-pic）_3] Cl_2EtOH在光诱导下对称性降低。(4)在佐贺大学，讨论了同步辐射和激光结合用于光致现象的未来前景。

In order to investigate the photo-induced phase transitions, we have been developing new techniques based on the combination of synchrotron radiation and laser in recent years.(1) We have constructed the new fast data acquisition system at the XAFS station of KEK-PF, where intense X-rays from a wiggler can be used. The system is powerful to investigate the photo-induced structural change since XAFS can provide the local atomic distance between the constituents. The system was applied to a spin crossover complex, resulting in the new information of the crystal structure of photo-induced phase.(2) We have also constructed the combination photoelectron system based on the synchrotron radiation and laser at UVSOR, Institute for Molecular Science. AT beam lines BL5A and BL6A2, core-level photoelectron spectroscopy was carried out to investigate the photo-induced surface photo voltage on GaAs. The photo-induced phase transition on a single crystal of [Fe(2-pic)_3] Cl_2EtOH. was also investigated with photoelectron spectroscopy using synchrotron radiation and laser. The UPS spectra of valence states of Fe(2-pic)_3] Cl_2EtOH did not show any change by laser excitation at room temperture, but it showed clearly that the valence states drastically changed by cooling the sample from RT to 40K and also by the laser-excitation at 40K. The experimental results indicate that the electronic structure of the photo-induced phase is not the same as that of the high-spin state.(3) At Kyoto university single crystals of spin crossover complexes were grown and the ESR and Raman systems were constructed to investigate the photo-induced phase transition. The Raman spectroscopy results indicated the clear evidence of the symmetry lowering in the photo-induced phase of [Fe(2-pic)_3] Cl_2EtOH.(4) AT Saga University, the future prospect of the combinational use of synchrotron radiation and laser for photo-induced phenomena was discussed.