The 5d photoabsorption spectra of Pb III and Bi IV

The photoabsorption spectra of lead and bismuth ions have been recorded using the dual laser plasma (DLP) technique in the photon energy range 30–66 eV. The experimental observations and theoretical calculations are focused on the 5d inner-shell excitations of the Hg I like ions of lead (Pb III) and bismuth (Bi IV). With the aid of Hartree–Fock calculations in the jj coupling scheme, we have identified over 30 new lines in both ions. As a result of the new measurements in Bi IV, the previously determined first ionization potential of Bi III has been increased from 45.32 eV to 45.36 eV.