Discrete structure in the 4d photoabsorption spectrum of antimony and its ions

The 4d inner-shell absorption spectra of Sb, Sb⁺, Sb²⁺ and Sb³⁺ have been obtained with the dual-laser-produced plasma technique. Discrete structure has been observed in the 30-40 eV region and identified as originating from 4d-5p transitions by comparison with the results of Hartree-Fock calculations performed within the superposition of configurations method. For comparison of theoretical and experimental spectra, 4d photoabsorption cross sections were calculated which took non-radiative decay rates into account. It was found to be necessary to include absorption from excited states of the ground configurations, especially in the higher ionization stages. Synthetic spectra, which allowed for thermal lower state population distributions, were produced and these are in agreement with the experimental data.