http://hdl.handle.net/2248/5817 Wed, 15 Apr 2026 22:05:38 GMT 2026-04-15T22:05:38Z http://hdl.handle.net/2248/5821 Fine Structure in the Arc Spectra of Indium and Thallium Narayan, A. L Indium.-The hyperfine structures of a few indium arc lines have been reported by Jackson1 and McLennan.2 Jackson observed that each of the lines l2S½-22P½ and is a quartet; while McLennan observed only three components. McLennan deduced a value i=½ for the nuclear moment, while Jackson, from intensity considerations and the structures of the lines, inferred as the more probable value of the nuclear spin. Restricted Access Sat, 17 Oct 1931 00:00:00 GMT http://hdl.handle.net/2248/5821 1931-10-17T00:00:00Z http://hdl.handle.net/2248/5820 Spectra of doubly and trebly ionised thallium Narayan, A. L; Pattabhi, P; Rao, A. S CONTINUING our previous work on Tl II and Pb III, the spectra of Tl III and Tl IV have been under examination by us for some time past. A preliminary attempt, by the application of the X-ray doublet-laws, revealed a number of regularities consisting of mainly the regular doublet terms. As a result of further attempts, it has now been possible to identify the inverted 2D term (5d96s2) and the quartet terms of (5d96s6p) and (5d96s6d) configurations. The starting point for the discovery of the inverted 2D term was given by the identification of 76150, 81834, and 100452 as 6s'2D – 7p2P. The super multiplet accompanying the electron transition 6p'6d' contains about forty lines in the ultra-violet. A few combinations due to transitions 6p7s have also been established. The (5d96s2) 2D term interval is found to be 18618. The combinations that could not be identified are either very faint or out of range. Restricted Access Fri, 20 Sep 1929 00:00:00 GMT http://hdl.handle.net/2248/5820 1929-09-20T00:00:00Z http://hdl.handle.net/2248/5819 The second spark spectrum of lead Rao, A. S; Narayan, A. L THE second spark spectrum of lead was recently analysed by K. R. Rao and ourselves; and a preliminary report of the series regularities discovered was published in a paper (Ind. J. Phy., vol. 2, pt. 4, pp. 468-476.) We have since become aware of a similar publication by Smith (Proc. N. A. S., vol. 14, pp. 878-880; 1928). There is a good agreement between our results and those of Smith, except in the identification of I 3P - I 3S 1. Evidently he has our I 3 S as his I 3P1 Carrol has very irregular intensities for the lines suggested by him. The I 3S1suggested by us is supported by the location of the second series I 3 S - 2 3P, I 3D - 2 3P, and 2 3P -2 3 S. Furthermore, 1 3P - I 3S suggested by us is given additional support by the closeness with which it follows the irregular doublet law, for the isoelectronic sequences, Hg I, Tl II, and Pb III. An interchange of his levels I 3S1 and I 3P1 would probably bring the whole scheme into alinement with ours. As a result of our attempts to get further regularities, we have been able to get 2 3P -2 3D and 2 3P -2 3P as well. Restricted Access Sat, 23 Nov 1929 00:00:00 GMT http://hdl.handle.net/2248/5819 1929-11-23T00:00:00Z http://hdl.handle.net/2248/5818 Spectrum of doubly ionised arsenic Rao, A. S; Narayan, A. L THE deepest term of the separation of doubly ionised arsenic (As III) is 4p 2P1. The values of these doublet terms relative to 2G were reported in a recent paper (Ind. J. Phy., 5, 3, p. 3) to be 220, 221 cm.-1. It was found in the course of this work that a number of lines that could be attributed to doubly ionised arsenic remained unclassified. The spectrum has been further investigated. About fortyfive of these unclassified lines have entered into quartet systems, the terms identified being: Restricted Access Sat, 10 Aug 1929 00:00:00 GMT http://hdl.handle.net/2248/5818 1929-08-10T00:00:00Z