PRC

[paper] Magnetic moment of 104Agm and the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei

Magnetic moment of 104Agm and the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei

V.V. Golovko et al.

doi: 10.1103/PhysRevC.81.054323

Nuclear magnetic resonance (NMR/ON) measurements with β- and γ-ray detection have been performed on oriented 104Agg,m nuclei with the NICOLE 3He-4He dilution refrigerator setup at ISOLDE/CERN. For 104Agg (Iπ=5+) the γ-NMR/ON resonance signal was found at ν=266.70(5) MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature (<1 K) is found to be |Bhf(AgFe)|=44.709(35) T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, |Bhf(AgFe)|=44.692(30) T. For 104Agm (Iπ=2+), the anisotropy of the β particles provided the NMR/ON resonance signal at ν=627.7(4) MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment μ(104mAg)=+3.691(3) μN, which is significantly more precise than previous results. The magnetic moments of the even-A 102-110Ag isotopes are discussed in view of the competition between the (πg9/2)7/2+-3(νd5/2νg7/2)5/2+ and the (πg9/2)9/2+-3(νd5/2νg7/2)5/2+ configurations. The magnetic moments of the ground and isomeric states of 104Ag can be explained by an almost complete mixing of these two configurations.

[paper] g factor of the 44Cl ground state: Probing the reduced Z=16 and N=28 gaps

g factor of the 44Cl ground state: Probing the reduced Z=16 and N=28 gaps

M. De Rydt et al.

doi: 10.1103/PhysRevC.81.034308

The g factor of the 44Cl ground state is measured at the LISE fragment separator at the Grand Acclérateur National d’Ions Lourds (GANIL) using the β nuclear magnetic resonance technique, resulting in g(44Cl)=(-)0.2749(2). An analysis of the g factor value and of the theoretical level scheme in the shell-model framework reveals the presence of odd-proton s1/2 configurations and neutron excitation across the N=28 shell gap in the ground state of 44Cl. In addition, the measured g factor strongly supports a 2 spin assignment for the 44Cl ground state.

[paper] Magnetic dipole moments of 57,58,59Cu

Magnetic dipole moments of 57,58,59Cu

T.E. Cocolios et al.

doi: 10.1103/PhysRevC.81.014314

In-gas-cell laser spectroscopy of the isotopes 57,58,59,63,65Cu has been performed at the LISOL facility using the 244.164-nm optical transition from the atomic ground state of copper. A detailed discussion on the hyperfine structure of 63Cu is presented. The magnetic dipole moments of the isotopes 57,58,59,65Cu are extracted based on that of 63Cu. The new value μ=+0.479(13)μN is proposed for 58Cu, consistent with that of a πp3/2⊗νp3/2 ground-state configuration. Spin assignments for the radioactive isotopes 57,58,59Cu are confirmed. The isotope shifts between the different isotopes are also given and discussed.

[paper] Hyperfine field of einsteinium in iron and nuclear magnetic moment of 254Es

Hyperfine field of einsteinium in iron and nuclear magnetic moment of 254Es

N. Severijns et al.

10.1103/PhysRevC.79.064322

The angular distributions of γ rays and α particles from oriented 250Bk, 253,254Es, and 255Fm nuclei were investigated to extract hyperfine interaction information for these actinide impurities in an iron host lattice. The hyperfine field of einsteinium in iron was found to be |Bhf(EsFe̲ |)=396(32) T. With this value the magnetic moment of 254Es was then determined as |μ|=4.35(41) μN.

[paper] Up to N3LO heavy-baryon chiral perturbation theory calculation for the M1 properties of three-nucleon systems

Up to N3LO heavy-baryon chiral perturbation theory calculation for the M1 properties of three-nucleon systems

Y.-H. Song et al.

10.1103/PhysRevC.79.064002

M1 properties, comprising magnetic moments and radiative capture of thermal neutron observables, are studied in two- and three-nucleon systems. We use meson exchange current derived up to N3LO using heavy baryon chiral perturbation theory à la Weinberg. Calculations have been performed for several qualitatively different realistic nuclear Hamiltonians, which permits us to analyze model dependence of our results. Our results are found to be strongly correlated with the effective range parameters such as binding energies and the scattering lengths. Taking into account such correlations, the results are in good agreement with the experimental data with small model dependence.

[paper] Doubly-magic nature of 56Ni: Measurement of the ground state nuclear magnetic dipole moment of 55Ni

Doubly-magic nature of 56Ni: Measurement of the ground state nuclear magnetic dipole moment of 55Ni

J.S. Berryman et al.

doi: 10.1103/PhysRevC.79.064305

The nuclear magnetic moment of the ground state of 55Ni (Iπ=3/2, T1/2=204 ms) has been deduced to be |&mul(55Ni)|=(0.976&plusminus;0.026) μN using the β-ray detecting nuclear magnetic resonance technique. Results of a shell model calculation in the full fp shell model space with the GXPF1 interaction reproduce the experimental value. Together with the known magnetic moment of the mirror partner 55Co, the isoscalar spin expectation value was extracted as <Σσz>=0.91&plusminus;0.07. The <Σσz> shows a trend similar to that established in the sd shell. The present theoretical interpretations of both &mul(55Ni) and <Σσz> for the T=1/2, A=55 mirror partners support the softness of the 56Ni core.

[paper] Nuclear structure of the even-even argon isotopes with a focus on magnetic moments

Nuclear structure of the even-even argon isotopes with a focus on magnetic moments

S.J.Q. Robinson et al.

10.1103/PhysRevC.79.054322″

We study the role of configuration mixing in the heavier even-even isotopes of argon. We begin by limiting the configurations of the even-even Ar isotopes to (d3/22)&pi (f7/2n)ν. There, due to the particular location in this shell-model space of 40Ar and 44Ar, we find that the spectra, B(E2)’s, and magnetic moments of these two nuclei are identical. Any deviation from this equality is direct evidence of configuration mixing. In a larger shell-model space there are significant differences between these two nuclei, with 44Ar being more collective. We also consider other even-even isotopes of argon and study how their nuclear structure effects evolve with N. We compare in the full 0ℏ ω space (sd)π (fp)ν the results of calculations with the WBT interaction and with the newer SDPF, denoted SDPF-U, interaction.

[paper] g factors of first 2+ states of neutron-rich Xe, Ba, and Ce isotopes

g factors of first 2+ states of neutron-rich Xe, Ba, and Ce isotopes

C. Goodin et al.

10.1103/PhysRevC.79.034316

Using new techniques developed for measuring angular correlations with large detector arrays, the g factors of 2+ states in 140,142Xe are measured for the first time by the method of correlation attenuation in randomly oriented magnetic fields. g factors in 146Ba and 146,148Ce are measured to establish the method by comparison with previous values. The results are discussed in terms of IBM-2 and rotation-vibration models.

[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.

[paper] Ground-state electric quadrupole moment of 31Al

Ground-state electric quadrupole moment of 31Al

D. Nagae et al.

The ground-state electric quadrupole moment of 31Al(Iπ=5/2+,T1/2=644(25) ms) has been measured by means of β-ray-detected nuclear magnetic resonance spectroscopy using a spin-polarized 31Al beam produced in the projectile fragmentation reaction. The obtained Q moment, |Qexp(31Al)|=112(32) e mb, is in agreement with conventional shell model calculations within the sd valence space. Previous results on the magnetic moment also support the validity of the sd model in this isotope, and thus it is concluded that 31Al is located outside of the island of inversion