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

Changes in mean-squared charge radii and magnetic moments of Tl179–184 measured by in-source laser spectroscopy

“…This interpretation is supported by the isotope and isomer-shift measurements which provide evidence for the marked difference between the radii for the ground and the isomeric (intruder) states in the odd-A 185−197 Tl (see Ref. [7] and references therein). This difference is explained by the corresponding change in quadrupole deformation.…”

“…The thallium (Tl) (Z = 81) isotope chain is intermediate between the Pb (Z = 82) and the Hg (Z = 80) chains, therefore it is important to extend the Tl systematics of IS and hyperfine structure (hfs) measurements far in the neutron-deficient region where the Hg systematics differ greatly from those of Pb. So far IS and hfs measurements are limited for the ground states down to 183 Tl and for the isomeric states down to 185 Tl [7,8]. In the spherical shell-model approach, the spin parity of I π = 1/2 + for the ground states of all presently known odd-A Tl isotopes can be understood as being due to the "normal" π 3s 1/2 proton-hole orbital.…”

“…In particular, long-lived high-spin intruder states of presumably [πlh 9/2 × ν1i 13/2 ] 7 − −10 − origin are well known in the odd-odd 184−200 Tl isotopes, and their tentative spin-parity assignments are based on decay spectroscopy experiments [2,10]. So far, laser spectroscopy studies of these isomers have been restricted to 186 Tl only [7]. In Ref.…”

Laser and decay spectroscopy of the short-lived isotope Fr214 in the vicinity of the N=126 shell closure

“…In this paper we focus on the charge radii in the trans-lead region and in particular, the characteristic increase in the gradient that is observed at a shell closure crossing. This is often referred to as a "kink" [4] and has already been seen at N = 126 in the neighboring isotopes from thallium to radium [5][6][7][8][9][10][11][12].…”

“…Although data for the trans-lead region is available from N = 132 onwards, little is known for N = 127-131 due to the short lifetime of the isotopes immediately after the N = 126 shell closure. Only four N = 127 isotones have been studied: 81 Tl [5], 82 Pb [6], 83 Bi [7], and 84 Po [18]. With five protons located in the π 1h 9/2 orbital, 214 Fr offers an additional test of the robustness of the Z = 82 shell closure.…”