Hyperfine-state-dependent lifetimes along the Ni-like isoelectronic sequence

An investigation of the lifetime of the 3d⁹4s ³D₃ level along a part of the nickel-like isoelectronic sequence has been performed. The focus of this work has been to evaluate the importance of the hyperfine induced electric quadrupole channel of the 3d¹⁰ ¹S₀-3d⁹4s ³D₃ transition for isotopes with nuclear spin. Comparisons between the magnetic octupole transition rate and the hyperfine-induced electric quadrupole transition rate shows that the hyperfine quenching is of importance along the whole isoelectronic sequence. At the low-Z end the hyperfine induced electric quadrupole transition channel dominates, being several orders of magnitude larger than the rate for the magnetic octupole transition channel, while for higher Z the two rates are of comparable size.