Zeeman Effect Data for the Spectra of Lanthanum—La I and La II

Zeeman effect data are given for 152 lines of La I and 506 lines of La II in the wave-length range 2257A to 7484A. Spectrograms were made at fields of 81,230, 83,370, and 86,570 oersteds using a Bitter electromagnet, and the 24 plates obtained with three diffraction gratings operating simultaneously were measured with an automatic comparator. g values are given for almost all of the classified terms of La I and La II, and the determinations from various lines agree usually to within 0.004 g unit. This makes available an array of unusually precise data for the evaluation of perturbations in typical rich two-electron and three-electron spectra. The g-sum rule of Pauli is verified in a number of cases to within a few tenths of a percent.