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

研制了一台时间分辨扫描红外光谱仪，它由球光源、单色器、MCT探测器、矩形积分器、连续调Q Nd：YAG激光器和微机组成。该谱仪既能观察到时间分辨谱（频率扫描模式），又能观察到瞬态信号的时间变化（时间扫描模式）。它覆盖了700 - 4200 cm^的光谱范围<-1>，时间分辨率为1 μ s。强度变化小至1/10^4，可以用5 mm的狭缝宽度（<-1>在700 cm@&gt;D1-1@&gt;D1时为6 cm^，<-1>在4000 cm^时为60 cm^<-1>）和100 cm^ /5 min的典型扫描速率<-1>检测。该光谱仪的高性能是通过使用高重复频率（750 Hz）激光作为光化光源并结合交流耦合检测方案实现的。用该光谱仪观测了无金属的τ型酞菁微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减动力学。

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.