The spectrum of trebly-ionized lead, Pb IV

Abstract

Carroll, Smith, Rao and Narayan and Schoepfle have established terms of the one-electron configurations of Pb IV. Schoepfle, whose analysis is the most complete, has identified the 6 s , 7 s , 8 s , 6 p 7 p , 6 d , 7 d , 5 f doublets, and in addition assigned a number of terms to the many-electron configurations that have as limit the 5 d 9 6 s configuration of Pb V. The Au I iso -electronic sequence, especially the configurations involving the 5 d 9 core, has been under investigation in this laboratory for some time. The analysis of Au I and of Hg II have been published and that of Pb IV is presented here. The investigation of Tl III is practically completed and will be published soon; Bi V is partially analysed. The state of our work on Tl III and Bi V is mentioned here because certain terms of these spectra and the corresponding terms of Pb IV have been established mainly by the regularity of the Moseley curves for these terms throughout the sequence Au I to Bi V. Thus the analysis of one spectrum has been facilitated and confirmed by a knowledge of the others. It is certain that some of the terms of Pb IV would not have been found except by such a method.