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 neutron-deficient isotopes $^{179–184}Tl$ 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 $^{179,181,183}Tl$ have 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 $^{182,184}Tl$ from the trend of the heavier Tl nuclei is observed. The charge radii of the ground states of the isotopes $^{179–184}Tl$ follow the trend for isotonic (spherical) lead nuclei. The noticeable difference in charge radii for ground and isomeric states of $^{183,184}Tl$ 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 $^{183}Tl$ has been found.