Development of a Microsecond Time-resolved Infrared Spectrometer and Its Applications to Photochemical Intermediates

建立了一台时间分辨扫描红外光谱仪，该光谱仪由全球光源、单色器、MCT探测器、箱车积分器、连续q开关ND:YAG激光器和一台个人计算机组成。该光谱仪既能观测到时间分辨光谱（频率扫描模式），又能观测到瞬态信号的时间变化（时间扫描模式）。光谱范围为700 ~ 4200 cm^<-1>，时间分辨率为1 μ m。狭缝宽度为5mm (700 cm@>D1-1@>D1时为6 cm^<-1>, 4000 cm^<-1>时为60 cm^<-1>)，典型扫描速率为100 cm^<-1>/5分钟。采用高重复频率（750 Hz）激光作为光化光源，结合交流耦合检测方案，实现了该光谱仪的高性能。用该光谱仪观测了无金属的tau型酞菁细颗粒的时间分辨红外光谱。阐明了光生三重态激子的衰变动力学。还观察了反式聚乙炔中光生带电孤子的衰变动力学。

A time-resolved scanning infrared spectrometer had been constructed which consists of a globar light source, a monochromator, an MCT detector, a boxcar integrator, a cw Q-switch ND:YAG laser, and a personal computer. Both the timeresolved spectra (in the frequency scanning mode) and the temporal change of the transient signals (in the time scanning mode) can be observed with this spectrometer. It covers the spectral range of 700 4200 cm^<-1> with the time resolution of 1 mus. Intensity changes as small as one part in 10^4 can be detected with a slit width of 5 mm (6 cm^<-1> at 700 cm@>D1-1@>D1 and 60 cm^<-1> at 4000 cm^<-1>) and with a typical scanning rate of 100 cm^<-1>/5 min. High performance of this spectrometer has been achieved by the use of a high repetition rate (750 Hz) laser for the actinic light source combined with an ac-coupled detection scheme. Time-resolved infrared spectra of metal-free tau-form phthalocyanine fine particles have been observed with this spectrometer. The decay dynamics of photogenerated triplet exciton have been elucidated. The decay dynamics of photogenerated charged solitons in trans-polyacetylene have also been observed.