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

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 4s${}^2$4p${}^5$, 4s${}^2$4p${}^4$4$\mathrm{\ell }$, 4s4p${}^6$, 4s${}^2$4p${}^4$5$\mathrm{\ell }$, 4s${}^2$4p${}^3$4d${}^2$, 4s4p${}^5$4$\mathrm{\ell }$, and 4s4p${}^5$5$\mathrm{\ell }$ configurations. Extensive configuration interaction has been included and the general-purpose relativistic atomic structure package ({\sc 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.