Radiative rates for E1, E2, M1, and M2 transitions in the Br-like ions Sr IV, Y V, Zr VI, Nb VII, and Mo VIII

Abstract

Energies and lifetimes are reported for the lowest 375 levels of five Br-like ions, namely Sr IV, Y V, Zr VI, Nb VII, and Mo VIII, mostly belonging to the 4s24p5, 4s24p44ℓ, 4s4p6, 4s24p45ℓ, 4s24p34d2, 4s4p54ℓ, and 4s4p55ℓ configurations. Extensive configuration interaction has been included and the general-purpose relativistic atomic structure package (grasp) has been adopted for the calculations. Additionally, radiative rates are listed among these levels for all E1, E2, M1, and M2 transitions. From a comparison with the measurements, the majority of our energy levels are assessed to be accurate to better than 2%, although discrepancies between theory and experiment for a few are up to 6%. An accuracy assessment of the calculated radiative rates (and lifetimes) is more difficult, because no prior results exist for these ions.