Laser-rf double-resonance measurements of the hyperfine structure ini49

The hyperfine structures of six metastable levels arising from the 3${\mathit{d}}^2$4s and 3${\mathit{d}}^3$ configurations in ${}_{}{}^{49}{}_{}{}^{}\mathrm{i}$ have been measured with high precision using the laser-rf double-resonance technique in a collinear laser–ion-beam geometry. The hfs constants A and B were determined to about 4 and 43 kHz, respectively. Less precise results are also reported for the 2${\mathit{p}}_{1/2}$ level of the 3${\mathit{d}}^3$ configuration and for five upper levels in the 3${\mathit{d}}^2$4p configuration. For these states, the optical spectra had Doppler widths of about 40 MHz, leading to A values determined to about 1 MHz. The results are compared with the presently available Hartree-Fock (HF) calculations. Good agreement is obtained with the HF results only in some cases. Substantial corrections due to many-body interactions and relativistic effects are required for other cases.