Self-consistent field calculation of the electronic structure of the uranyl ion (UO2++)

Using the multiple-scattering Xα method the electronic ground state (1Σ+g) of the UO++2 molecule has been calculated self-consistently. The self-consistent calculations were performed at three U–O bond distances [3.269, 4.269, and 5.269 (a.u.)]. The four highest occupied one-electron levels (σg, σu, Πg, Πu) of the ground state, which have received so much attention in the past, change ordering with decreasing bond distance but are so close in energy that the ordering may be unimportant in determining the absorption spectra. We have also computed the electronic transition energies for the excitations 1Σ+g → 1,3Φg(σ1uφ1u), 1Σ+g → 1,3Δg(σ1uφ1u), 1Σ+g → 1,3Πu, 1,3Φu(π3gδ1u), 1Σ+g → 1,3Δg, 1,3Γg(π3uφ1u), and 1Σ+g → 1,3Φg, 1,3Πg(π3uφ1u). All of these excitation energies fall in the region of the experimental absorption spectrum.