RESUMO
The changes in the mean-square charge radius (relative to ^{209}Bi), magnetic dipole, and electric quadrupole moments of ^{187,188,189,191}Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in ^{187,188,189}Bi^{g}, manifested by a sharp radius increase for the ground state of ^{188}Bi relative to the neighboring ^{187,189}Bi^{g}. A large isomer shift was also observed for ^{188}Bi^{m}. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment.
RESUMO
The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-uv excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in (127)Cd and (129)Cd for the first time. One essential feature of the spherical shell model is unambiguously confirmed by a linear increase of the 11/2(-) quadrupole moments. Remarkably, this mechanism is found to act well beyond the h(11/2) shell.
RESUMO
Multiconfiguration Dirac-Fock models have been employed to compute the electric field gradient in the ground state of the neutral bismuth atom. Combined with the experimental electric quadrupole hyperfine interaction constant, one obtains for (209)Bi the nuclear quadrupole moment Q = -516 (15) mb, which is almost 40% away from the previously accepted standard value [ -370 (26) mb], and narrows by over an order of magnitude the long-standing, extremely broad array of various results ranging from -370 to -710 mb. The recent Q values of (202-208,210(m)-213)Bi by Pearson et al. suffer a consequent change.
