Multireference relativistic configuration-interaction calculations for (d+s)ntransition-metal atomic states: Application to Zr ii hyperfine structure

Our relativistic configuration-interaction (RCI) methodology has been extended to multireference cases, and improved to permit the construction of angular-momentum functions of arbitrary size, and to minimize the number of vectors needed with each configuration. We report RCI calculations on the fine (fs) and hyperfine (hfs) structure for the (d+s${)}^3$ J=0.5 and 1.5 levels of Zr i i. The average fs error is 0.075 eV, and 17% for hfs, when compared to available experiment. These results indicate that it is possible to correctly position all levels of (d+s${)}^{\mathit{n}}$ configurations in the transition-metal atoms.