Fine Structure in the Arc Spectra of Bromine and Iodine

Abstract

Bromine.—The fine structures of a number of bromine arc lines have been previously reported by Hori.¹ By assuming that the lines λλ6632, 6560, 6351, 6149 have identical structures, De Bruin² inferred that the nuclear spin is 32. The fine structure measurements have been considerably extended, using a high frequency (15 megacycles) electrodeless discharge in pure bromine vapour and a Fabry-Perot interferometer. All the observed structures arise from the 4p⁴5s electron configuration, as was to be expected. Although the lines employed by De Bruin have not identical structures, as he supposed, the value of i = 32 has been confirmed. There is evidence that the two isotopes of bromine (79, 81) have the same nuclear spin.