On the series spectra of palladium

Abstract

In a previous paper the authors have given a preliminary analysis of the are spectrum of palladium. This has now been extended and brought into better agreement with the theoretical considerations of Hund. In addition, some progress has been made in the analysis of the second or spark spectrum of palladium. The work on the arc spectrum has been made possible by the study of the Zeeman effect of the palladium arc by Beals, by the experiments of McLennan and Cohen, and McLeannan and Liggett on the absorption spectrum of normal palladium vapour, and by the measurements of Meggers of the lines of the palladium arc in the region from 4500 to 9000 A. The ground Terms of Palladium I . On the basis of his experiments on the Zeeman effect, Beals assigned most of the strongest lines of the arc spectrum of combinations between a group of low terms designated by 1 S 0 , 3 D 321 , 1 D 2 (in the notation of Russell) and a group of singlet and triplet, P, D ¯ and F terms. This has been generally confirmed, although it has been necessary to rearrange the PDF group slightly in order to bring it into agreement with the theoretical grouping of these terms. The new arrangement of the lines involved is shown in Table I, and is supported by consideration of the relative intensity. Those lines for which the agreement between observed and calculated Zeeman effect is particularly good are not affected by the changes. Table I also contains other lines due to combinations with the low group, some of which have been identified as the second members of series of which the lines given by Beals are the first members. The nature of the other terms combining with the low group has not been ascertained.