NANOSECOND TIME-RESOLVED INFRARED-SPECTROSCOPY WITH A DISPERSIVE SCANNING SPECTROMETER

A nanosecond time-resolved infrared spectroscopic system based on a di spersive scanning spectrometer has been constructed. This is an advanc ed version of a similar system reported in a previous paper; the time resolution has been improved from 1 mus to 50 ns and the sensitivity f rom 10(-4) in intensity changes to 10(-6). These have been achieved by the use of a high-temperature ceramic infrared light source, a photov oltaic MCT detector, and a low-noise, wide-band preamplifier developed specifically for the present purpose. Time-resolved infrared spectra of a few samples of photochemical and photobiological interests are pr esented to show the capability of the system. The origin of the therma l artifacts, which have been found to hamper the time-resolved infrare d measurements seriously, is shown to be due to the transient reflecta nce change induced by a small temperature jump. The future prospect of time-resolved infrared spectroscopy is discussed with reference to ot her methods including infrared laser spectroscopy and Fourier transfor m infrared spectroscopy.