Screening Constant by Unit Nuclear Charge Photoionization of Rb\(²⁺\) Ions

Photoionization data of the trans-Fe element Rb\({}²⁺\) are reported. Rydberg series 4s\({}²\)4p\({}⁴\)(\({}¹\)D\({}₂\))nd and 4s\({}²\)4p\({}⁴\)(\({}³\)P\({}₁\))nd Rydberg series of Rb\({}²⁺\) from the \({}²\)P\({}^∘\)\({}₃\)\({}/\)\({}₂\) ground state and the \({}²\)P\({}^∘\)\({}1/2\) metastable state of Rb\({}²⁺\) converging respectively to the 4s\({}²\)4p\({}⁴\)(\({}¹\)D\({}₂\)) 4s\({}²\)4p\({}⁴\)(\({}³\)P\({}₁\)) series limit in Rb\({}³\)\({}⁺\) are considered.\ Calculations are performed in the framework of the Screening constant by unit nuclear charge (SCUNC) method. Accurate data are tabulated up to $n=40$.\ It is shown that the SCUNC analytical formulas reproduce with an excellent precision, recent ALS measurements of Macaluso et al. [J. Phys. B: At. Mol. Opt. Phys. 49 (2016), 235002; 50 (2017), 119501)]. The energy deviations with respect to the ALS data are equal to 0.001 eV. New data are tabulated for \(n=21-40\).