Abstract
In very pure nitrogen, at high current and pressure, the relative intensities of the bands emitted by the positive column are reversed as compared with those emitted in the conventional discharge. The second positive system, although ordinarily dominating, may be completely suppressed and the N2+ bands strongly enhanced. We attribute the reversal to excitation and ionization in steps via metastable levels. Their low ionization potential limits the energy of the electrons. Possibly the reversal is enhanced by a selection rule. This process, excluding the second positive bands, is contrasted with processes exciting the same bands as the only visible system, namely, the blue afterglow and recombination of atoms on a copper surface. In these experiments, the first positive bands, although not observed, are inevitably excited by cascading but fail to exhibit strong vibration. This limits them to the infrared, visually unobservable range.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
