Synchrotron-radiation X-ray structural analysis of photo-excited state

本项目的目的是利用时间分辨光谱研究过渡金属络合物中的光诱导现象，并用第三代同步辐射X射线对其结构进行研究，以阐明光诱导效应。研究了BL02B2偏转磁铁光束线在光照射下的结构，并在BL40XU波荡器光束线上建立了时间分辨X射线衍射仪。主要结果如下：(1)我们发现了[Fe(Ptz)_6](BF_4)_2在光激发下动力学稳态的一级相变。我们进一步研究了达到稳态的时间行为，阐明了光生高自旋物种的化学压力效应在动态相变中起着重要作用。(2)实现了[Fe(Phen)_2](NCS)_2自旋态的开关。我们进一步测定了[Fe(Phen)_2](NCS)_2的MEM电荷密度(3)研究了层状反铁磁结构的LaMnO_3自旋体系的光响应。并发现临界慢化行为消失。(4)在BL40XU波荡器光束线上建立了时间分辨衍射仪。(5)测量了高光子灵敏度RbMn[Fe(CN)_6]的MEM电荷密度。(6)我们合成了价控的Co-Fe氰基桥联过渡金属薄膜，并测定了其电子相图。(7)通过飞秒时间分辨光谱，我们发现了Co-Fe氰化物的寿命伸长行为

The purpose of this project is to search the photoinduced phenomena in transition metal complexes by means of the time-resolved spectroscopy, and to clarify to photoinduced effect vy the structural investigation with use of the 3rd generation synchrotron-radiation x-ray. We investigated the structure under photo-irradiation at the BL02B2 bending magnet beamline, and built a time-resolved x-ray diffraction apparatus at the BL40XU undulator beamline. The followings are the main results.(1) We have found a first-order phase transition of the dynamical steady state of [Fe (ptz)_6] (BF_4)_2 under photo-excitation We further investigated the temporal behavior to reach the steady state and clarified that the chemical pressure effect of the photo-created high-spin species play an important role in the dynamical phase transition.(2) WE realized the on/off switching od the spin state of [Fe (phen)_2] (NCS)_2. We further determined the MEM charge density of both the phases.(3) We investigated the photo-response of the spin system of LaMnO3 with layered-type antiferromagnic structure, and found that the critical slowing-down behavior disappears.(4) We have built the time-resolved diffraction apparatus at the BL40XU undulator beamline(5) The have determined the MEM charge density of highly photon sensitive RbMn[Fe (CN)_6]. We further clarified the valence state of by means of the electrostatic potential imaging.(6) We have synthesized the valence-controlled Co-Fe cyano-bridged transition metal films, and determined the electronic phase diagram.(7) BY means of the femto-second time-resolved spectroscopy, we have found a lifetime elongation behavior of the Co-Fe cyanide