Interpretation of the solution absorption spectra of the (PuO2)++ and (NpO2)+ ions

Eleven years ago we proposed a model for the electronic configuration of ions of the uranyl type. The solution absorption spectra of the (PuO2) ++ and (NpO2) ions are here interpreted on the basis of this model. The interpretation is based on exact calculations, and on plausible arguments about the strengths and widths of the absorption peaks. If suitable values are chosen for the Coulomb integrals, the spin-orbit coupling constant, and the ligand field parameters then the calculated energy levels agree well with the observed positions of the absorption peaks.