The intensities of bands in the spectrum of boron monoxide

The intensities of the α bands of BO have been measured by means of an arrangement which gives the intensity of a whole band. Precautions for the detection of systematic errors are described, and the probable error is estimated at about ± 5 per cent. The observed intensities have been compared with theoretical ones calculated from wave mechanics. Morse's wave function is found to give much better results than the harmonic wave function, but shows some discrepancy from theory for higher vibrational states. The theory using the harmonic wave function has been applied to some previous results for the intensities of the β bands of BO. Fair agreement is found for the most part, but a few bands show discrepancies greater than the experimental error. The intensity ratio of the B 11 O and B 10 O bands has been measured for two of the α bands. The result, 3.5:1, is in satisfactory agreement with a previous determination of the isotope intensity ratio in the β bands of BO, 3.66:1.