M1-E2 interference in the Zeeman spectra of Pb I and Pb II

Studies of the M1-E2 interference effect in the Zeeman spectra of two mixed-type forbidden lines, 733.2 nm of Pb I and 710.2 nm of Pb II, are reported. In the experiment, the odd isotope 207 of Pb was used. By the use of computer modelling techniques the simulated contours were fitted to the recorded spectra in order to determine the electric-quadrupole admixture in forbidden lines. The E2 admixtures found are (4.12 ± 0.07)% for the 733.2 nm line and (4.25 ± 0.18)% for the 710.2 nm line of Pb II. Our results are compared with recent theories and other experiments.