Energies and transition data for Be-like hafnium and tantalum ions.

Energies and lifetimes of the lowest 178 levels belonging to the 1 s 2 2 s 2 , 1 s 2 2 s 2 p , 1 s 2 2 p 2 , 1 s 2 2 s n l , and 1 s 2 2 p n l (n = 3 − 6 ; l = 0 − 5) configurations in Be-like hafnium and tantalum ions (Hf LXIX and Ta LXX) have been computed, as well as transition wavelengths, transition probabilities, line strengths, and weighted oscillator strengths of the electric/magnetic dipole (E1/M1) and electric/magnetic quadrupole (E2/M2) transitions between these levels. The calculations have been carried out using the GRASP2018 code through the multiconfiguration Dirac–Hartree–Fock (MCDHF) method with the Breit interaction and quantum electrodynamics (QED) corrections. The present results have been compared with previous data. Furthermore, the values of the last two active sets were compared to estimate the accuracy. • Comprehensive calculations of atomic data for Hf LXIX and Ta LXX. • The MCDHF method has been utilized through the GRASP2018 code. • The accuracy of atomic parameters has been estimated. [ABSTRACT FROM AUTHOR]