radii

[paper] In-gas-cell laser spectroscopy of the magnetic dipole moment of the N≈126 isotope ¹⁹⁹Pt

In-gas-cell laser spectroscopy of the magnetic dipole moment of the N≈126 isotope ¹⁹⁹Pt

Y. Hirayama et al.
doi: 10.1103/PhysRevC.96.014307

The magnetic dipole moment and mean-square charge radius of $199 g Pt$ $(I^{π} =$ $5 / 2^{-}, t_{1 / 2} = 30.8$ min) ground state and $199 m Pt$ $(E_{ex} = 424$ keV, $I^{π} =$ (13/2) $^{+}, t_{1 / 2} = 13.6$ s) isomeric state are evaluated for the first time from investigations of the hyperfine splitting of the $λ_{1} = 248.792$ nm transition by in-gas-cell laser ionization spectroscopy. Ground and isomeric states of neutron-rich $199 Pt$ nucleus were produced by a multinucleon transfer reaction at the KEK Isotope Separation System (KISS), designed for the study of nuclear spectroscopy in the vicinity of $N = 126$ . The measured magnetic dipole moments $+ 0.75$ (8) $μ_{N}$ and $- 0.57$ (5) $μ_{N}$ are consistent with the systematics of those of nuclei with $I^{π} =$ $5 / 2^{-}$ and $I^{π} =$ $13 / 2^{+}$ , respectively.

Jul 11, 2017 by Theo experiment g factor radii 0

[paper] Onset of deformation in neutron-deficient Bi isotopes studied by laser spectroscopy

Onset of deformation in neutron-deficient Bi isotopes studied by laser spectroscopy

A.E. Barzakh et al.

doi: 10.1103/PhysRevC.95.044324

In-source laser spectroscopy experiments for bismuth isotopes at the 306.77-nm atomic transition has been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of Petersburg Nuclear Physics Institute. New data on isotope shifts and hyperfine structure for Bi ground states and isomers (^{189,190m1,190m2,191,192,192m,194,194m,198m}Bi) have been obtained. The changes in the mean-square charge radii δ⟨r²⟩ and magnetic-moment values have been deduced. For Bi nuclei a marked deviation from the isotopic trend of δ⟨r²⟩ in lead and thallium isotopic chains has been demonstrated at N<111. This has been interpreted as an indication of the onset of quadrupole deformation. Analysis of the magnetic moments for odd-odd Bi isotopes also points to the possible increase in deformation at N<111.

Apr 30, 2017 by Theo experiment g factor radii 0

[Paper] Radii and Binding Energies in Oxygen Isotopes: A Challenge for Nuclear Forces

Radii and Binding Energies in Oxygen Isotopes: A Challenge for Nuclear Forces

V. Lapoux et al.
doi: 10.1103/PhysRevLett.117.052501

We present a systematic study of both nuclear radii and binding energies in (even) oxygen isotopes from the valley of stability to the neutron drip line. Both charge and matter radii are compared to state-of-the-art ab initio calculations along with binding energy systematics. Experimental matter radii are obtained through a complete evaluation of the available elastic proton scattering data of oxygen isotopes. We show that, in spite of a good reproduction of binding energies, ab initio calculations with conventional nuclear interactions derived within chiral effective field theory fail to provide a realistic description of charge and matter radii. A novel version of two- and three-nucleon forces leads to considerable improvement of the simultaneous description of the three observables for stable isotopes but shows deficiencies for the most neutron-rich systems. Thus, crucial challenges related to the development of nuclear interactions remain.

Jul 29, 2016 by Theo radii theory 0

[paper] Structural evolution in transitional nuclei of mass 82≤A≤132

Structural evolution in transitional nuclei of mass 82≤A≤132

M. Bhutan

doi: 10.1103/PhysRevC.92.034323

In this theoretical study, we report an investigation on the behavior of two-neutron separation energy, a differential variation of the nucleon separation energy, the nuclear charge radii, and the single-particle energy levels along the isotopic chains of transitional nuclei. We have used the relativistic mean-field formalism with NL3 and NL3* forces for this present analysis. The study refers to the even-even nuclei such as Zr, Mo, Ru, and Pd for N=42−86, where a rich collective phenomena such as proton radioactivity, cluster or nucleus radioactivity, exotic shapes, island of inversion, etc. are observed. We found that there are few nonmonotonic aspects over the isotopic chain, which are correlated with the structural properties such as shell/subshell closures, the shape transition, clustering, magicity, etc. In addition to these, we have shown the internal configuration of these nuclei to get a further insight into the reason for these discrepancies.

Oct 3, 2015 by Theo radii theory 0

[paper] The energy-weighted sum rule and the nuclear radius

The energy-weighted sum rule and the nuclear radius

Hans Peter Schröder

doi: 10.1140/epja/i2015-15109-9

The energy-weighted integrated cross-section for photon absorption –known as sum rule σ−1 — is under certain conditions proportional to the mean square nuclear radius (Levinger, Bethe (Phys. Rev. 78, 115 (1950))). Due to the energy weight factor the low-energy absorption components are emphasized and the dipole transitions in the region of giant resonances contribute enhanced at σ−1 . Thus, the cross-section of the full interaction can be replaced in good approximation by the dipole cross-section. Under these aspects, we have calculated σ−1 and the radii of various gg-nuclei. For our purpose, we have chosen a simple shell model where the integrals can be solved analytically, and the contributions of uncorrelated functions and correlation corrections can be shown explicitly. The mean square radius as a function of σ−1 differs by a factor of 1.5/0.87 from the previous result of Levinger and Kent (Phys. Rev. 95, 418 (1954)) without correlation corrections. Plotting the function of the correlation corrections g(A) and the uncorrelated function f(A) as a ratio it shows that g(A)/f(A) tends towards a limit. Finally, our results for the radii of gg-nuclei are in good agreement with recent experiments (I. Angeli, K.P. Marinova, At. Data Nucl. Data Tables 99, 69 (2013)).

Oct 2, 2015 by Theo radii theory 0

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