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Title: Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei

Abstract

In recent years fully consistent quasiparticle random-phase approximation (QRPA) calculations using finite range Gogny force have been performed to study electromagnetic excitations of several axially-symmetric deformed nuclei up to the {sup 238}U. Here we present the extension of this approach to the charge-exchange nuclear excitations (pnQRPA). In particular we focus on the Isobaric Analog and Gamow-Teller resonances. A comparison of the predicted GT strength distribution with existing experimental data is presented. The role of nuclear deformation is shown. Special attention is paid to β-decay half-lives calculations for which experimental data exist and for specific isotone chains of relevance for the r-process nucleosynthesis.

Authors:
 [1];  [2];  [1];  [3]
  1. Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles, CP-226, 1050 Brussels (Belgium)
  2. (France)
  3. CEA, DAM, DIF, F-91297 Arpajon (France)
Publication Date:
OSTI Identifier:
22436704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Data Sheets; Journal Volume: 120; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; AXIAL SYMMETRY; BETA DECAY; CHARGE EXCHANGE; DEFORMED NUCLEI; GAMOW-TELLER RULES; HALF-LIFE; ISOBARIC ANALOGS; NUCLEAR DEFORMATION; NUCLEOSYNTHESIS; R PROCESS; RANDOM PHASE APPROXIMATION; URANIUM 238

Citation Formats

Martini, M., E-mail: martini.marco@gmail.com, CEA, DAM, DIF, F-91297 Arpajon, Goriely, S., and Péru, S. Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei. United States: N. p., 2014. Web. doi:10.1016/J.NDS.2014.07.027.
Martini, M., E-mail: martini.marco@gmail.com, CEA, DAM, DIF, F-91297 Arpajon, Goriely, S., & Péru, S. Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei. United States. doi:10.1016/J.NDS.2014.07.027.
Martini, M., E-mail: martini.marco@gmail.com, CEA, DAM, DIF, F-91297 Arpajon, Goriely, S., and Péru, S. 2014. "Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei". United States. doi:10.1016/J.NDS.2014.07.027.
@article{osti_22436704,
title = {Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei},
author = {Martini, M., E-mail: martini.marco@gmail.com and CEA, DAM, DIF, F-91297 Arpajon and Goriely, S. and Péru, S.},
abstractNote = {In recent years fully consistent quasiparticle random-phase approximation (QRPA) calculations using finite range Gogny force have been performed to study electromagnetic excitations of several axially-symmetric deformed nuclei up to the {sup 238}U. Here we present the extension of this approach to the charge-exchange nuclear excitations (pnQRPA). In particular we focus on the Isobaric Analog and Gamow-Teller resonances. A comparison of the predicted GT strength distribution with existing experimental data is presented. The role of nuclear deformation is shown. Special attention is paid to β-decay half-lives calculations for which experimental data exist and for specific isotone chains of relevance for the r-process nucleosynthesis.},
doi = {10.1016/J.NDS.2014.07.027},
journal = {Nuclear Data Sheets},
number = ,
volume = 120,
place = {United States},
year = 2014,
month = 6
}
  • Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed with the D1S Gogny force. Dipole responses have been calculated in Ne isotopes to study the existence of soft dipole modes in exotic nuclei. A comparison between QRPA and generator coordinate method with Gaussian overlap approximation results is done for low lying 2{sup +} states in N = 16 isotones and Ni isotopes.
  • Fully consistent axially-symmetric-deformed quasiparticle random phase approximation calculations have been performed with the D1S Gogny force. Giant resonances in exotic nuclei as well as in deformed Mg and Si isotopes have been studied. Dipole responses have been calculated in Ne isotopes and N=16 isotones to study the existence of soft dipole modes in exotic nuclei. The same formalism has been used to describe multipole responses up to octupole in the deformed and heavy nucleus {sup 238}U. Low energy spectroscopy of nickel isotopes has been studied, revealing 0{sup +} states which display a particular structure.
  • Expressions for electron scattering form factors for odd-A deformed nuclei are derived by projecting states with definite angular momentum from an axially symmetric intrinsic wave function. Through an expansion of the multipole matrix elements in terms of 1/ both single-particle and collective contributions are taken into account in a systematic way. Selection rules are discussed and some schematic calculations of magnetic form factors are presented for /sup 25/Mg and /sup 181/Ta.
  • The magnetic octupole moments of twenty odd-A nuclei whose energy levels are described by the axiallysymmetric collective model in strong coupling were calculated. With but two exceptions, the predicted moments are of the same magnitude as or larger than the moments measured for seven nuclei. The model parameters were determined by fitting the measured values of the lower moments and transition probabilities. The assumption is made that the orbital gyromagnetic ratio for the odd nucleon is that of a free particle. Then from the total gyromagnetic ratio of the particle, which was determined from the measured magnetic dipole moment andmore » M1 transition probabilities, the spin gyromagnetic ratio, g/sub s/, was determined. With but one exception gs was found to have a value between the free particle and pure Dirac particle values. (auth)« less
  • It is shown that in the Bohr Hamiltonian the use of three different mass coefficients for the two vibrational and the rotational modes is very important for the correct description of the properties of the well deformed axially symmetric nuclei. Four parameters per nucleus are needed to describe the relative values of energies and B(E2)'s.