Studies on ultrafast reaction processes in solution and establishment of exciplex picosecond dynamics

(1)用皮秒(Ps)和纳秒(Ns)激光光解方法，通过时间分辨发射、瞬时吸收和光电流测量，研究了激基络合物和激发的单重态EDA络合物在极性溶剂中的动力学行为.(2)我们证实了TMPD和相关的二胺在某些极性溶剂中由于电子从荧光态转移到溶剂团簇而发生了光致电荷分离.此外，我们还用紫外光PS多光子激光光解方法探测到了非极性溶剂中ET产生的从Rydberg态芘到联苯的超短寿命离子对。(3)从光合作用模型体系的单重态和极性溶剂中的强EDA络合物出发，阐明了超快速非辐射失活的机理，论证了两步ET在卟啉-苯醌复合体系中的重要性。此外，还对PAI和GT的超快非辐射失活机理进行了探讨。-电子氢键体系。(4)我们建立了紫外光PS多光子激光光解方法，用于研究纯液体和聚合物薄膜等分子聚集体的激发态和电离态的动力学，并应用于醇、烷基苯和烷烃。(5)我们阐明了A-CH=CH-D型化合物的光致分子内电荷转移与反式异构化的关系。(6)在上述激光光解研究结果的基础上，考虑到电离态和中性态溶剂光子频率的巨大差异，我们发展了光致CS和产生的自由基离子对的电荷复合反应的能隙依赖新理论，并表明该理论可以令人满意地解释观测结果。

(1) We have elucidated dynamic behaviors of exciplex systems and excited singlet EDA complexes in polar solvents by means of time-resolved emission, transient absorption and photocurrent measurements with picosecond (ps) and nanosecond (ns) laser photolysis methods.(2) We have confirmed that TMPD and related diamines in some polar solvents undergo photoinduced charge separation (CS) due to the electron transfer (ET) from fluorescent state to solvent cluster. Moreover, we have deteced ultrashort-lived ion pair produced by ET from Rydberg state pyrene to biphenyl in nonpolar solvent with ultraviolet ps multiphoton laser photolysis method.(3) We have elucidated the mechanism of the ultrafast nonradiative deactivation from the singlet ET state of porphyrin-quinone photosynthetic model systems and strong EDA complexes in polar solvents and have demonstrated the importance of the two step ET in porphyrin-quinone combined systems. Moreover, the mechanism of ultrafast nonradiative deactivation of <pai> -electronic hydrogen bonded systems have been elucidated.(4) We have established the method of ultraviolet ps multiphoton laser photolysis method for investigating the dynamics of excited and ionized states of molecular aggregates such as pure liquids and polymer films and have applied to alcohols, alkylbenzenes and alkanes.(5) We have elucidated the relation between the photoinduced intramolecular charge transfer and trans-cis isomerization of A-CH=CH-D type of compounds.(6) On the basis of above results of laser photolysis investigations, we have developed a new theory of the energy gap dependence of photoinduced CS and charge recombination reaction of produced radical ion pairs taking into consideration the large difference of the solvent photon frequency between the ionized and neutral state and have shown that the observed results can be interpreted satisfactorily by this theory.