Supersonic jet absorption spectrometry utilizing a xenon flashlamp and a monochromator equipped with a photodiode array

A multichannel spectrometric system is constructed for measurements of an absorption spectrum for a sample in a supersonic jet. The system consists of a xenon flashlamp and a monochromator equipped with a photodiode array. This instrument covers 18.5 nm with 512 diode arrays, and the data are accumulated during 32 min to improve the signal-to-noise ratio. The absorption spectrum is obtained simply by subtracting the sample signal (I) from the reference signal (I0). The spectrum is measured for benzene and its analogs in spectral regions of 254–312 nm. The typical signal intensities are 0.5%, the noise level being reduced to 0.005% by averaging 9600 data. The amount of sample required for recording a spectrum is ca. 100 mg for aniline.