Probing the single-particle behavior above 132Sn via electromagnetic moments of 133,134Sb and N=82 isotones

Magnetic and quadrupole moments of the 7/2(+) ground state in Sb-133 and the (7(-)) isomer in Sb-134 have been measured by collinear laser spectroscopy to investigate the single-particle behavior above the doubly magic nucleus Sn-132. The comparison of experimental data of the 7/2(+) states in Sb-133 and neighboring N = 82 isotones to shell-model calculations reveals the sensitivity of magnetic moments to the splitting of the spin-orbit partners pi 0g(9/2) and pi 0g(7/2) across the proton shell closure at Z = 50. In contrast, quadrupole moments of the N = 82 isotones are insensitive to cross-shell excitations, but require the full proton model space from Z = 50 to 82 for their accurate description. In fact, the linear trend of the quadrupole moment follows approximately the expectation of the seniority scheme when filling the pi 0g(7/2) orbital. As far as the isomer in Sb-134 is concerned, its electromagnetic moments can be perfectly described by the additivity rule employing the moments of Sb-133 and Sn-133, respectively. These findings agree with shell-model calculations and thus confirm the weak coupling between the valence proton and neutron in Sb-13(4).

Automated summary

The single-particle behavior of Sb-133 nuclei is highly sensitive to the splitting of spin-orbit partners, while quadrupole moments of N = 82 isotones are insensitive to cross-shell excitations. The isomer in Sb-134 can be accurately described using the additivity rule for magnetic moments.