Search

Abstract: We report changes in mean-square charge radii, , magnetic moments and quadrupole moments for three multi-quasi particle isomers; 97m2Y, 176mYb and 178m1Hf. All the isomers are observed to display a decrease in compared to the lower-lying nuclear state on which the isomer is built. The decreases in occur despite the isomers showing increases in quadrupole moment. Possible mechanisms for the effect, which is now seen for six multi-quasi particle isomers, are discussed. [Copyright &y& Elsevier]

The spectroscopic quadrupole moments of the odd–even Mn isotopes between N = 28 and N = 38 have been measured using bunched-beam collinear laser spectroscopy at ISOLDE, CERN. In order to increase sensitivity to the quadrupole interaction, the measurements have been done using a transition in the ion rather than in the atom, with the additional advantage of better spectroscopic efficiency. Since the chosen transition is from a metastable state, optical pumping in ISOLDE's cooler and buncher (ISCOOL) was used to populate this state. The extracted quadrupole moments are compared to large-scale shell model predictions using three effective interactions, GXPF1A, LNPS and modified A3DA. The inclusion of both the 1 ν g 9 / 2 and 2 ν d 5 / 2 orbitals in the model space is shown to be necessary to reproduce the observed increase in the quadrupole deformation from N = 36 onwards. Specifically, the inclusion of the 2 ν d 5 / 2 orbital induces an increase in neutron and proton excitations across the reduced gaps at N = 40 and Z = 28 , leading to an increase in deformation above N = 36 . [ABSTRACT FROM AUTHOR]

The magnetic dipole and the spectroscopic quadrupole moments of the nuclear ground states in the odd-mass nickel isotopes 59−67Ni have been determined using collinear laser spectroscopy at the CERN-ISOLDE facility. They are compared to ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) calculations including contributions of two-body currents as well as to shell-model calculations. The two-body-current contributions significantly improve the agreement with experimental data, reducing the mean-square deviation from the experimental moments by a factor of 3 to 5, depending on the employed interaction. For all interactions, the largest contributions are obtained for the 5 2 − ( 7 2 −) isotopes 65Ni (55Ni), which is ascribed to the high angular momentum of the f orbitals. Our results demonstrate that the inclusion of two-body-current contributions to the magnetic moment in an isotopic chain of complex nuclei can be handled by the VS-IMSRG and can outperform phenomenological shell-model calculations using effective g -factors in the nickel region. [ABSTRACT FROM AUTHOR]

Nuclear moments of the antimony isotopes 113−133Sb are measured by collinear laser spectroscopy and used to benchmark phenomenological shell-model and ab initio calculations in the valence-space in-medium similarity renormalization group (VS-IMSRG). The shell-model calculations reproduce the electromagnetic moments over all Sb isotopes when suitable effective g -factors and charges are employed. Good agreement is achieved by VS-IMSRG for magnetic moments on the neutron-deficient side for both odd-even and odd-odd Sb isotopes while its results deviate from experiment on the neutron-rich side. When the same effective g -factors are used, VS-IMSRG agrees with experiment nearly as well as the shell model. Hence, the wave functions are very similar in both approaches and missing contributions to the M1 operator are identified as the cause of the discrepancy of VS-IMSRG with experiment. Electric quadrupole moments remain more challenging for VS-IMSRG. [ABSTRACT FROM AUTHOR]

The electric quadrupole moment of 49Sc was measured by collinear laser spectroscopy at CERN-ISOLDE to be Q s = − 0.159 (8) e b, and a nearly tenfold improvement in precision was reached for the electromagnetic moments of 47,49Sc. The single-particle behavior and nucleon-nucleon correlations are investigated with the electromagnetic moments of Z = 21 isotopes and N = 28 isotones as valence neutrons and protons fill the distinctive 0 f 7 / 2 orbit, respectively, located between magic numbers, 20 and 28. The experimental data are interpreted with shell-model calculations using an effective interaction, and ab-initio valence-space in-medium similarity renormalization group calculations based on chiral interactions. These results highlight the sensitivity of nuclear electromagnetic moments to different types of nucleon-nucleon correlations, and establish an important benchmark for further developments of theoretical calculations. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on the ground state nuclear moments measured in 58–62Cu using collinear laser spectroscopy at the ISOLDE facility. The quadrupole moments for 58–60Cu have been measured for the first time as , , and with higher precision for 61,62Cu as , . The magnetic moments of 58,59Cu are measured with a higher precision as and . The experimental nuclear moments are compared to large-scale shell-model calculations with the GXPF1 and GXPF1A effective interactions, allowing the softness of the 56Ni core to be studied. [Copyright &y& Elsevier]