The Zeeman Effect of Lead II, III and IV

Zeeman Effect of Pb II, III and IV, have been studied at fields of about 40,000 gauss with the newly completed outfit at the Mendenhall Laboratory. Gieseler's results on Pb II are in general correct, although a few minor discrepancies have been found. The 6d²D₃ level shows an anomalous g-value which may be attributed to the fact that the 6d²D levels are inverted, or to perturbations caused by neighboring configurations. In Pb III a similar perturbation is found in the $6s7p$ configuration. Here the g-sum of ³P₁ and ¹P₁ is slightly higher than the theoretical value, while the ³P₂ level, which should be unaffected by ordinary changes in coupling, yields a value 1.35 instead of 1.50.