Open AccessThe structure of the spectrum of ionised nitrogen
Publication year - 1925
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1925.0003
Subject(s) - multiplicity (mathematics) , spectral line , nitrogen , nitrogen atom , emission spectrum , spectrum (functional analysis) , yield (engineering) , physics , atomic physics , mathematics , quantum mechanics , geometry , group (periodic table) , thermodynamics
In accordance with recent developments in the analysis of spectra, it is to be expected that, while the neutral atom of nitrogen (N·I) will yield a spectrum derived from systems of terms of even multiplicity, the spectrum of ionised nitrogen (N II or N+ ) will be constituted from terms of odd multiplicity. The spectrum of doubly-ionised nitrogen (N III or N++ ) is similarly expected to be formed from terms of even multiplicity. The probable existence of the three types of line spectra representing N I, N II and N III has already been pointed out, but few details regarding the regularities in the respective spectra have hitherto been available. A spectrum which probably represents N I has been described by Stark and Hardtke, but accurate measurements of the lines do not appear to have been made; Bowen and Millikan, however, have attributed to N I two well-known pairs of lines in the Schumann region at λλ 1745·3, 1742·7, 1494·8 and 1492·8. implying even multiplicity of the terms involved.