Electronic Spectrum of the NpO₂²⁺ and NpO₂⁺ Ions

The ground and excited states of the linear NpO 2 2+ and NpO 2 + ions have been calculated using relativistic spin−orbit configuration interaction methods based on effective core potentials. The f → f transitions and some charge-transfer transitions have been calculated for both ions and compared with experiment wherever possible. Various types of analysis are used to gain a better understanding of the types and patterns of electronic states.