Zeeman Effect of the Forbidden Lines of Pb I II. An Interference Effect in the Mixed Line,λ7330

Abstract

The transverse Zeeman effect of this line, which contains mixed magnetic dipole and electric quadrupole radiation, is investigated with a Fabry-Perot interferometer, and with magnetic fields up to 4000 gauss. The pattern obtained, -2.68, -2.42, (-1.49), (-1.215), (-0.945), -0.255, 0, 0.255, (0.945), (1.215), (1.47), 2.42, 2.68, is in substantial agreement with expectations. Quantitative intensity measurements of all components are reported. In the $\sigma$ pattern, the sum of the intensities of the four outer electric quadrupole components is found to be 0.02 of the three central magnetic dipole components. The relative intensities of the latter, 28, 45 and 27, and of the $\pi$ components, agree with the theory developed in the following article by E. Gerjuoy, provided that the intensities contributed by the Zeeman components of the hyperfine structure are taken into account. These components are investigated at various magnetic fields, and the development of the Back-Goudsmit effect is verified. For the six $\pi$ components, in the above order, the measured intensities at 3880 gauss are 22, 23, 7, 7, 18 and 23. Comparison with theory indicates 2.2±0.5 percent of quadrupole radiation, and proves that interference exists between the two types of radiation.