In a study of the spectra of organic compounds excited by streaming active nitrogen, the intensification of certain pairs of lines in the violet CN bands was observed. This phenomenon was reported recently by Herzberg who likened this intensification to the resonance-fluorescence of iodine. The cause, according to Herzberg, is absorption of radiation of short wave-length from nitrogen bands in the far ultra-violet. Experiments were made to test this explanation. Radiation from the nitrogen discharge was found to have no effect on the appearance or non-appearance of these intensified doublets. Additional experiments were made to observe the effect of pressure on the appearance of the intensification, and it was found that such intensification depends upon the pressure under which the excitation of the CN spectrum occurs. It appears that the intensification results through collision with some higher-energy atomic or molecular species whose formation is suppressed at higher pressures.

• Received 10 June 1929

DOI:https://doi.org/10.1103/PhysRev.34.453