Spectra and critical potentials of fifth group elements

Spectra and critical potentials of fifth group elements

Author: Ruark, A.E. Mohler, F.L. Foote, P.D. Chenault, R.L.

Year: 1924

This paper discusses the arc spectra and critical potentials of arsenic, antimony, and bismuth, revised values of the critical potentials being given, while information on the spectrum of singly ionised nitrogen and the various spark spectra of bismuth is included. The resonance potentials of the neutral atoms are found to correspond to the mean excitation voltages of groups of spectra lines. Photographs of the thermionic discharge in bismuth were used to separate the excitation stages of the bismuth atom; groups of spark lines appear at 14 +/- 1 and 25 +/- 5 volts. The description is very complete of the experimental work undertaken and of the voluminous data obtained. The bismuth absorption spectrum was studied in detail, while classifications of lines of N/sup +/, As, Sb, Bi, and Bi/sup +/ were obtained. As, Sb, and Bi are found to have doublet spectra, and, to describe phenomena connected with the existence of very narrow doublet levels in Al/sup +/, Bi, and other elements, it is proposed to introduce a new quantum number, termed the fine quantum number. The paper is replete with tables and illustrations.