A system was developed for the measurement of the infrared fluorescence spectra (IR-F spectra) excited with the 10.6 μm lines from a CO
2 laser. It was shown that by use of this system, the IR-F spectra could successfully be measured for several kinds of organic compounds in the gaseous state, in spite of the relatively small output power of the laser used (3W). The observed spectra were compared with the corresponding infrared absorption spectra, and the various features of the spectral patterns of the IR-F were pointed out. The experimental problems such as the correction of the background emission, the spectral sensitivity of the instrument, the influence of self-absorptions, the appearance of the reflection line of the exciting laser light, etc., were discussed. Furthermore, the relations between the IR-F intensities and the concentrations of a sample were examined. It was shown that in the case of the IR-F spectrometry, the analytical curves are not always linear, and differ among the bands even of the same compound. Finally, the problems of the present measurement system were discussed mainly in view of the improvement of the sensitivity.
View full abstract