Photoionization study of K III and Br IV ions in the framework of the modified orbital atomic theory

Resonance energies and quantum defects are reported for several Rydberg series for K2+ and Br3+. For K III ions, the [3s23p4 (1D2)]nd (2P,2D) and [3s3p5 (3P°2,0,1)]np, [3s23p4 (1S0)]nd (2D5/2,3/2) Rydberg series originating from the 3s23p5 (2P°1/2) metastable and 3s23p5 (2P°3/2) ground states are considered. For Br IV ions, the study is focused on the 4s24p (1D2, 3P2, 3P1)nd series originating from the 4s24p2 (1D2,3P2,3P1) states along with the 4s4p2 (3P1)np and 4s4p2 (1D2)np states originating from the 4s24p2 (3P1, 1D2) states. Calculations are performed in the framework of the modified atomic orbital theory (MAOT). Precise data are tabulated up to high excited stated n = 40. The results presented in this paper are in excellent agreement with the synchrotron radiation measurements of Alna'Washi et al. (Phys Rev A 90:023417, 2014) on K2+ and of Macaluso et al. (J Phys B At Mol Opt Phys 52:145002, 2019) on Br3+. These excellent agreements between theory and experiments indicate that the MAOT formalism can be used to report accurate high-lying excited Rydberg series of atomic species for the diagnostic and the modeling of astrophysical or laboratory plasmas.