Hartree-Fock calculations for the 4d95s25p64f configuration in La IV

Abstract

Recently discrete resonances in the photoabsorption spectrum of La near the 4d electron threshold have been identified as combinations between the ground-state of La IV, 4d¹⁰5s²5p^{6 1}S₀, and the J=1 levels of the 4d⁹5s²5p⁶4f configuration, the strongest combination being with 4d⁹4f¹P₁. The agreement was satisfactory between energies from observations and from ab initio calculations except for ¹P₁, for which the energy predicted by using wavefunctions determined for the mean energy of the whole configuration is about 14 cV too high. The present Hartree-Fock calculation for the ¹P term removes half of this discrepancy. Part of the remaining discrepancy may be caused by solid state effects. The relevance of this result for calculations of photoionization in Ar I and Xe I is pointed out.