Investigations of Rydberg series from photoionization processes of N3+, O4+, and Ar8+ ions

•Accurate energy resonances of N3+ (2pnl) 1P°, 1s22p [2P°] np 3P states and of O4+ 1s22p [2P°] np 3P states (n=5–30).•Accurate energy positions of 1s22s2p6 (2S1/2) np 1P° series of Ar8+ up to n=5–36.•Excellent agreements with experiment and theory.•New energy resonances of 1s22p [2P°] np 3P series (n=5–30) in Be-like Mg8+, Si10+, and P11+ ions.•Benchmark data for the modeling of astrophysical and laboratory plasmas.

We report accurate energy resonances from the 1s22s21S0→(2pnl) 1P° transitions in the Be-like N3+ ions along with energy resonances of the 1s22s2p 3P0→1s22p [2P°] np 3P transitions in the Be-like N3+ and O4+ ions. Energy positions of the 1s22s2p6 (2S1/2) np 1P° Rydberg series of the Ar8+ ions converging to the 1s22s2p6 (2S1/2) series limit in Ar9+ are also reported. New energy resonances of the 1s22p [2P°] np 3P Rydberg series of the Be-like Mg8+, Si10+, and P11+ ions are tabulated. Calculations are performed using the Screening Constant by Unit Nuclear Charge (SCUNC) method. Excellent agreements with available experimental and theoretical literature data are found. The present calculations provide benchmark data for the diagnosis and for the modeling of astrophysical and laboratory plasmas.