Femtosecond Dynamics and Phase Relaxation of Electron Transfer Reaction in Double Metal Complex Crystals

在倾斜研究中，日本首次建造了飞秒空腔倾倒Ti：蓝宝石激光器。我们已经成功地将脉冲能量增加到10倍（35 fs， 20 nJ/脉冲），具有可变重复率（10 kHz-76 MHz），衍射效率为40-60%。虽然我们已经尝试在双金属复合晶体和光导电材料（如氧钛基酞菁）的晶体薄膜的泵探测量中测量相弛豫信号，但目前我们还没有成功地获得任何相弛豫信息。这是由于目前系统的泵-探针测量的信噪比较差，以及纯晶体中的一些热问题。我们正试图将这种方法应用于稀释的固体体系。利用该激光系统的时间相关光子计数，研究了来宾掺杂晶体中的能量转移反应。在高掺杂的Os^<2+>: [Ru(bpy)_3](PF_6)_2晶体中，^3CT（Ru）的主发射衰减是非指数的。衰变归因于能量转移的不同速率常数，这取决于激发的主客体距离，这些速率常数由于激发迁移通过宿主分子而改变。通过随机模拟，确定了最接近的Os（II）的速率为1.2 x 10^<10> s^<-1>，以及3 x 10^8 s^<-1>的激发迁移到最接近的Ru（II）。在金属中心最接近的条件下，能量迁移和转移的机制被认为是电子交换作用。

For the tilted study, a femtosecond cavity-dumped Ti : Sapphire laser has been constructed for the first time in Japan. We have succeeded to increase a pulse energy to 10 times (35 fs, 20 nJ/pulse) with variable repetition rates(10 kHz-76 MHz) in a diffraction efficiency (40-60%). Although we have tried to measure phase relaxation signals in pump-probe measurements of double metal complex crystals and thin crystal films of photo-conducting materials such as oxotitanylphthalocyanine, we could not succeed yet to get any information of phase relaxation in pump-probe measurements at this moment. This is due to a bad s/n ratio in pump-probe measurement of present our system and some thermal problems in neat crystals. We are trying to apply this method to diluted solid systems.Energy transfer reactions in guest-doped crystals have also been investigated by means of time-correlated photon-counting consists of this laser system. In the case of highly doped Os^<2+> : [Ru(bpy)_3](PF_6)_2 crystal, the host emission decay of ^3CT(Ru) was non-exponential. The decay is ascribed to the various rate constants of energy transfer depending on the excited host-guest distances, which are changed as a result of excitation migration through the host molecules. By a stochastic simulation, rates are determined to be 1.2 x 10^<10> s^<-1> for the closest Os(II) and 3 x 10^8 s^<-1> for the excitation migration to the closest Ru(II). The mechanism of energy migration and transfer in the closest condition of metal centers are ascribed to electron exchange interaction.