On the Absorption Spectrum of Hydrogen Chloride

The fundamental band and the harmonic band of hydrogen chloride have been measured with narrow slits. The lines of the fundamental as previously measured, have been resolved, each into two lines arising from the existence of the isotopes Cl₃₅ and Cl₃₇. The relative intensities of the lines in the two series are in accord with the accepted ratio for the abundance of the isotopes. In the harmonic, a slight separation of the lines arising from the isotopes had been previously achieved by Randall and Imes. In the present work the degree of separation is greatly enchanced. Wave-number and intensity determinations for the two series of lines in each band are submitted. Figures are given representing the bands in the new form. The ratio of the intensities of the fundamental and harmonic bands, as experimentally determined, is found to be in good agreement with the computed value.