Isotope shifts and hyperfine structure in near-ultraviolet transitions of Pb I by Doppler-free saturation spectroscopy

Abstract

Isotope shifts and hyperfine structures have been determined for the three near-ultraviolet transitions 405.8 nm ${(6s}^{2}{6p}^{2}{}^{3}{P}_{2}--{6s}^{2}6p7s{}^{3}{P}_{1}^{o}),$ 368.3 nm ${(6s}^{2}{6p}^{2}{}^{3}{P}_{1}--{6s}^{2}6p7s{}^{3}{P}_{0}^{o}),$ and 364.0 nm ${(6s}^{2}{6p}^{2}{}^{3}{P}_{1}--{6s}^{2}6p7s{}^{3}{P}_{1}^{o})$ in stable isotopes of Pb I using the technique of saturated absorption spectroscopy in a sputtered vapor. The isotope shifts for these transitions and the magnetic hyperfine interaction constants for the ${6s}^{2}{6p}^{2}{}^{3}{P}_{1,2}$ metastable levels are the first Doppler-free determinations for these systems reported in the literature to our knowledge. Combined with experimental data, previously given in the literature, and pseudorelativistic Hartree-Fock estimates, the field shifts (FS's) of seven relevant configurations are deduced: $\mathrm{FS}{(6s}^{2}6p7s)=2461\mathrm{MHz},$ $\mathrm{FS}{(6s}^{2}6p9p)=1838\mathrm{MHz},$ $\mathrm{FS}{(6s}^{2}6p6d)=1820\mathrm{MHz},$ $\mathrm{FS}{(6s}^{2}6p7d)=1668\mathrm{MHz},$ $\mathrm{FS}{(6s}^{2}6p8s)=2132\mathrm{MHz},$ $\mathrm{FS}{(6s}^{2}6p7p)=395\mathrm{MHz},$ and $\mathrm{FS}{(6s}^{2}6p5f)=\ensuremath{-}461\mathrm{MHz},$ referred to ${6s}^{2}{6p}^{2}.$ The hyperfine-structure integrals deduced from the experimental A factors for p electrons of the ground configuration ${6s}^{2}{6p}^{2}$ are in good agreement with results of ab initio calculations.