A New Rapid-Scan Infrared Spectrometer and the Emission Spectra Observed in the Explosion of CO-O₂ Mixtures

Abstract

A rapid-scan infrared spectrometer was developed by modifying a Shimadzu IR 27 G infrared spectrometer and was applied to the study of explosion reaction of CO-02 mixtures. The new instrument was equipped with a PbSe detector and a rapidly oscillating mirror. The scan rate was 125 cm-Vmsec at 3000 cm^-1 and 12 cm-Vmsec at 500 cm^-1. The repetition interval was 20 msec. The spectra which were successively obtained every 20 msec were simultaneously displayed on a multi-trace oscilloscope and photographed. The calculated resolving power was about 7 cm^-1 at the slit width of 500 gm and at the wave number of 3000 cm -1. The spectral performance of this instrument was tested by recording the absorption bands of HCl gas, and the well resolved vibration-rotation bands structure at around 2900 cm^-1 was observed. Full band width at half maximum of P(3) and P(4) were approximately 15 cm^-1 at the slit width of 700 pm.
The mixtures of CO and 02 were exploded by spark discharge in a cylindrical vessel of pyrex. The emission spectra of CO₂ after the ignition were recorded at around the wave number of 3600 cm^-1 and 2350 cm^-1, The band heads corresponding to the 001-000 and 011-* 010 transitions were observed in these spectra. The effect of addition of a small amount of H₂O was tested.