electromagnetic moments

[paper] Laser spectroscopy of atoms in superfluid helium for the measurement of nuclear spins and electromagnetic moments of radioactive atoms

Laser spectroscopy of atoms in superfluid helium for the measurement of nuclear spins and electromagnetic moments of radioactive atoms

T. Fujita et al.

doi: 10.1007/s10751-015-1206-0

A new laser spectroscopic method named “OROCHI (Optical RI-atom Observation in Condensed Helium as Ion catcher)” has been developed for deriving the nuclear spins and electromagnetic moments of low-yield exotic nuclei. In this method, we observe atomic Zeeman and hyperfine structures using laser-radio-frequency/microwave double-resonance spectroscopy. In our previous works, double-resonance spectroscopy was performed successfully with laser-sputtered stable atoms including non-alkali Au atoms as well as alkali Rb and Cs atoms. Following these works, measurements with 84−87Rb energetic ion beams were carried out in the RIKEN projectile fragment separator (RIPS). In this paper, we report the present status of OROCHI and discuss its feasibility, especially for low-yield nuclei such as unstable Au isotopes.

[preprint] Effective field theory for nuclear vibrations with quantified uncertainties

Effective field theory for nuclear vibrations with quantified uncertainties

E.A. Coello Pérez and T. Papenbrock

arXiv: 1510.02401

We develop an effective field theory (EFT) for nuclear vibrations. The key ingredients – quadrupole degrees of freedom, rotational invariance, and a breakdown scale around the three-phonon level – are taken from data. The EFT is developed for spectra and electromagnetic moments and transitions. We employ tools from Bayesian statistics for the quantification of theoretical uncertainties. The EFT consistently describes spectra and electromagnetic transitions for 62Ni, 98,100Ru, 106,108Pd, 110,112,114Cd, and 118,120,122Te within the theoretical uncertainties. This suggests that these nuclei can be viewed as anharmonic vibrators.

[paper] Nuclear charge radii and electromagnetic moments of radioactive scandium isotopes and isomers

Nuclear charge radii and electromagnetic moments of radioactive scandium isotopes and isomers

M. Avgoulea et al.

doi: 10.1088/0954-3899/38/2/025104

Collinear laser spectroscopy experiments with the Sc+ transition 3d4s 3D2 → 3d4p 3F3 at λ = 363.1 nm were performed on the 42–46Sc isotopic chain using an ion guide isotope separator with a cooler-buncher. Nuclear magnetic dipole and electric quadrupole moments as well as isotope shifts were determined from the hyperfine structure for five ground states and two isomers. Extensive multi-configurational Dirac–Fock calculations were performed in order to evaluate the specific mass-shift, MSMS, and field-shift, F, parameters which allowed evaluation of the charge radii trend of the Sc isotopic sequence. The charge radii obtained show systematics more like the Ti radii, which increase towards the neutron shell closure N = 20, than the symmetric parabolic curve for Ca. The changes in mean-square charge radii of the isomeric states relative to the ground states for 44Sc and 45Sc were also extracted. The charge radii difference between the ground and isomeric states of 45Sc is in agreement with the deformation effect estimated from the B(E2) measurements but is smaller than the deformation extracted from the spectroscopic quadrupole moments.

[paper] Charge radii and electromagnetic moments of Li and Be isotopes from the ab initio no-core shell model

Charge radii and electromagnetic moments of Li and Be isotopes from the ab initio no-core shell model

C. Forssén et al.

Recently, charge radii and ground-state electromagnetic moments of Li and Be isotopes were measured precisely. We have performed large-scale ab initio no-core shell model calculations for these isotopes using high-precision nucleon-nucleon potentials. The isotopic trends of our computed charge radii and quadrupole and magnetic-dipole moments are in good agreement with experimental results with the exception of the 11Li charge radius. The magnetic moments are in particular well described, whereas the absolute magnitudes of the quadrupole moments are about 10% too small. The small magnitude of the 6Li quadrupole moment is reproduced, and with the CD-Bonn NN potential, also its correct sign.