Hyperfine structure of low-lying triplet states in Sc45 II

Collinear laser spectroscopy experiments were performed on singly charged $^{45}\mathrm{Sc}$ ($^{45}\mathrm{Sc}$ II). Fourteen fine-structure transitions in the $3d4s\ensuremath{\leftrightarrow}3d4p$ configuration were studied for three sets of triplet states, the ${}^{3}{D}_{1}, {}^{3}{D}_{2}$, and ${}^{3}{D}_{3}$ states in the $3d4s$ configuration and the ${}^{3}{F}_{2}^{o}, {}^{3}{F}_{3}^{o}, {}^{3}{F}_{4}^{o}, {}^{3}{D}_{1}^{o}, {}^{3}{D}_{2}^{o}$, and ${}^{3}{D}_{3}^{o}$ states in the $3d4p$ configuration. Furthermore, the hyperfine magnetic dipole ($A$) and the electric quadrupole ($B$) coupling constants were determined. Detailed studies of experimental systematic uncertainties lead to accurate determination of the coupling constants and facilitate comparison with theoretical models, especially for $B$ constants. The improved experimental uncertainty reveals deviations from available theoretical calculations and suggests the need for further theoretical studies.