The Secondary Hydrogen Spectrum

Abstract

THE further examination of the secondary spectrum of hydrogen has led to a number of interesting discoveries since my last publication (Roy. Soc. Proc. A, vol. 111, p. 714, 1926). It appears that the green and red bands have the same electron jump but correspond to different sets of vibrational transitions, those for the green bands being 0→0, 1→1, 2→2, 3→3, and 4→4, and those for the red bands 1→0, 2→1, 3→2, 4→3, 5→3, and 6→5. In addition, there are five other less well developed sets of bands with the same electron jump, two in the infra-red with vibrational transitions 2→0, 3→1, 4→2 and 3→0, 4→1 respectively, and three on the violet side of the green with the respective sets of vibrational transitions 0→1, 1→2, 2→3, 3→4 and 0→2, 1→3 and 0→3. There is an intercombination between the lines of all the above bands and indications of a further combination in the members of the P R branches, which, however, are less well developed than the Q branches. The second differences of the Q branches form a square array with a common vertical difference = 2.4 and a common horizontal difference = 2.8 wave number.