Changes in the mean-square charge radii and magnetic moments of neutron-deficient Tl isotopes

Abstract

In-source laser spectroscopy experiments for neutron-deficient thallium isotopes at the 276.9-nm atomic transition have been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of Petersburg Nuclear Physics Institute. New data on isotope shifts and the hyperfine structure for ${}^{183\ensuremath{-}207}$Tl isotopes and isomers are presented. The changes in the mean-square charge radii and magnetic-moment values are deduced. It is shown that nuclear properties of Tl isotopes and isomers smoothly change at the neutron midshell and beyond without development of strong deformation in contrast to the adjacent Hg nuclei. A rather great isomer shift between $I$ $=$ 1/2 and $I$ $=$ 9/2 states for odd Tl isotopes is preserved for both sides of the previously investigated mass range. For the first time, a similar isomer shift is found for the odd-odd isotope ${}^{186}$Tl. The close resemblance of the charge radii isotopic behavior for the Tl and Pb ground states is demonstrated.