Lifetimes of different hyperfine levels of 3d<sup>9</sup>4s <sup>3</sup>D<sub>3</sub>, <em>τ<sub>F</sub></em>, relative to the lifetime of 3d<sup>9</sup>4s <sup>3</sup>D<sub>3</sub> which decays by the pure M3 transition, <em>τ<sub>M3</sub></em>

<p><strong>Figure 2.</strong> Lifetimes of different hyperfine levels of 3d<sup>9</sup>4s <sup>3</sup>D<sub>3</sub>, <em>τ<sub>F</sub></em>, relative to the lifetime of 3d<sup>9</sup>4s <sup>3</sup>D<sub>3</sub> which decays by the pure M3 transition, <em>τ<sub>M3</sub></em>. Results for all hyperfine levels of different isotopes in table <a href="http://iopscience.iop.org/0953-4075/46/14/145001/article#b467799t4" target="_blank">4</a> are presented.</p> <p><strong>Abstract</strong></p> <p>Based on the multi-configuration Dirac–Hartree–Fock method and using the GRASPVU package, a theoretical investigation was performed to study the lifetimes of hyperfine levels of the first excited level 3d<sup>9</sup>4s <sup>3</sup>D<sub>3</sub> in Ni-like ions (<em>Z</em> = 72–79) for all stable isotopes with nuclear spin. Comparisons between hyperfine-induced electric quadrupole transition rates and the pure magnetic octupole transition rates show that the extra electric quadrupole transition channel caused by the nuclear magnetic dipole and electric quadrupole hyperfine interaction is important for most hyperfine levels in each individual ion. Lifetimes of most hyperfine levels are sensitive to this extra decay channel. Extreme cases are found in <sup>181</sup>Ta, <sup>185</sup>Re and <sup>187</sup>Re, where lifetimes of some hyperfine levels are shortened by more than an order of magnitude.</p>