APS : Changes in mean-squared charge radii and magnetic moments of $^{179–184}$Tl measured by in-source laser spectroscopy

Hyperfine structure and isotope shifts have been measured for the ground and isomeric states in the neutrond-eficient isotopes 179-184TI using the 276.9-nm transition. The experiment has been performed at the CERN-Isotope Separator On-Line facility using the in-source resonance-ionization laser spectroscopy technique. Spins for the ground states in (179,181,183)TIhave been determined as I = 1/2. Magnetic moments and changes in the nuclear mean-square charge radii have been deduced. By applying the additivity relation for magnetic moments of the odd-odd Tl nuclei the leading configuration assignments were confirmed. A deviation of magnetic moments for isomeric states in (TI)-T-182,184 from the trend of the heavier Tl nuclei is observed. The charge radii of the ground states of the isotopes 179- 184TI follow the trend for isotonic (spherical) lead nuclei. The noticeable difference in charge radii for ground and isomeric states of (TI)-T-183,184 has been observed, suggesting a larger deformation for the intruder-based 9/2(-) and 10(-)states compared to the ground states. An unexpected growth of the isomer shift for (TI)-T-183 has been found.