Isotope shifts in electron affinities and in binding energies of Pb and hyperfine structure of 207Pb−.

The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for ^207–208Pb and −0.003(4) meV for ^206–208Pb by scanning the threshold of the photodetachment channel Pb⁻ ( S 3 / 2 ◦ 4 ) − Pb (³P₀), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to ³P₂ using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for ^207–208Pb and −0.001(14) meV for ^206–208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of ²⁰⁷Pb⁻, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of ^207–208Pb and ^206–208Pb are −0.0023(8) and −0.0037(13) meV for the ³P₀ channel, respectively, in good agreement with Walter et al.'s measurements. The isotope shifts in binding energies relative to ³P_1,2, −0.0015(8) and −0.0026(13) meV for ^207–208Pb and ^206–208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of ²⁰⁷Pb⁻ obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of ²⁰⁹Bi. [ABSTRACT FROM AUTHOR]