Search

We report on a set of high-precision measurements of nuclear binding and excitation energies, as well as nuclear spins, magnetic dipole and electric quadrupole moments of neutron-rich silver isotopes, 113−123Ag. The measurements were performed using the JYFLTRAP mass spectrometer and the collinear laser spectroscopy beamline at the Ion Guide Isotope Separator On-Line (IGISOL) facility. For the first time, we can firmly establish the ordering of the long-lived Iπ=1/2−,7/2+ states in these isotopes, and pin down the inversion of these two levels at either A=121(N=74) or A=123(N=76). We compare these findings to calculations performed with density functional theory (DFT), from which we establish the crucial role that the spin-orbit strength and time-odd mean fields play in the simultaneous description of electromagnetic moments and nuclear binding.

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.

High-precision quasisimultaneous collinear/anticollinear laser spectroscopy was used to measure the 4s^{2}S_{1/2}→4p^{2}P_{1/2} (D1) and the 4s^{2}S_{1/2}→4p^{2}P_{3/2} (D2) as well as the three 3d→4p transitions in the naturally abundant Ca^{+} isotopes. Thereby, accuracies of approximately 100kHz were achieved, which enabled an accurate determination of the field-shift ratio in the D2 and D1 lines through a King-plot analysis. Our value of F_{D2}/F_{D1}=1.0010(23) is in excellent agreement with current theoretical predictions, while former experimental results from ion-trap measurements showed a 3σ to 6σ deviation from theory introducing the so-called Ca^{+} field-shift puzzle. A successful check of consistency was made by combining the measurements of the D1 and D2 lines with those of the 3d→4p transitions and precise literature values for the 4s→3d and 3d^{2}D_{3/2}→3d^{2}D_{5/2} transitions. Failing for the previous ion-trap measurements, the check of consistency strongly indicates that our results constitute a solution to this puzzle, supporting the results of atomic theory.