Microscopic HFB + QRPA predictions of dipole strength for astrophysics applications

Goriely, Stéphane; Khan, E.; Samyn, M.

doi:10.1016/j.nuclphysa.2004.04.105

Cited by 285 publications

(361 citation statements)

References 40 publications

(83 reference statements)

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“…In the present case, the microscopic γ -ray strength functions from Ref. [29] have been used. The corresponding rms deviation [based on a relation identical to Eq.…”

Section: Resultsmentioning

confidence: 99%

Temperature-dependent combinatorial level densities with the D1M Gogny force

et al. 2012

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The combinatorial model of nuclear level densities has now reached a level of accuracy comparable to that of the best global analytical expressions without suffering from the limits imposed by the statistical hypothesis on which the latter expressions rely. In particular, it provides naturally, non-Gaussian spin distribution as well as nonequipartition of parities which are known to have a significant impact on cross section predictions at low energies. Our previous global model [S. Goriely, S. Hilaire, and A. J. Koning, Phys. Rev. C 78, 064307 (2008)] suffered from deficiencies, in particular in the way the collective effects-both vibrational and rotational-were treated. We have recently improved the level density calculations using simultaneously the single-particle levels and collective properties predicted by a newly derived Gogny interaction [S. Goriely, S. Hilaire, M. Girod, and S. Péru, Phys. Rev. Lett. 102, 242501 (2009)], therefore enabling a microscopic description of energy-dependent shell, pairing, and deformation effects. In addition, for deformed nuclei, the transition to sphericity is coherently taken into account on the basis of a temperature-dependent Hartree-Fock calculation which provides at each temperature the structure properties needed to build the level densities. This new method is described and shown to give reasonable results with respect to available experimental data.

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“…In the present case, the microscopic γ -ray strength functions from Ref. [29] have been used. The corresponding rms deviation [based on a relation identical to Eq.…”

Section: Resultsmentioning

confidence: 99%

Temperature-dependent combinatorial level densities with the D1M Gogny force

et al. 2012

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“…[13] and the recent reviews [21,22]). Second, this resonance is known to have a significant impact on the radiative neutron capture rate of astrophysical interest [14,15,23]. The importance of the PDR is confirmed by the simple fact that it has been taken into account in all modern nuclear data libraries (although at a phenomenological level) in addition to the usual GDR [20,24].…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7]21,[26][27][28] and references therein) studies. Even if the total E1 strength of the PDR is small, if it is located well below the neutron separation energy, it can significantly increase the radiative neutron capture cross section, especially for neutron-rich nuclei [14,15,23]. Different measurements suggest that some enhancement of the E1 strength could be located at low energies even in stable nuclei, a feature that cannot be described within the (Q)RPA calculations.…”

Section: Introductionmentioning

confidence: 99%

Self-consistent calculations of the strength function and radiative neutron capture cross section for stable and unstable tin isotopes

Авдеенков

Goriely²,

Kamerdzhiev

et al. 2011

Phys. Rev. C

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The E1 strength function for 15 stable and unstable Sn even-even isotopes from A = 100 to A = 176 are calculated using a self-consistent microscopic theory which, in addition to the standard (quasiparticle) randomphase approximation [(Q)RPA] approach, takes into account phonon coupling and the single-particle continuum (by means of the discretization procedure) with a cutoff of 100 MeV. Our analysis shows two distinct regions for which the integral characteristics of both the giant and pygmy resonances behave rather differently. For neutron-rich nuclei, starting from 132 Sn, we obtain a giant E1 resonance which significantly deviates from the widely used systematics extrapolated from experimental data in the β-stability valley. We show that the inclusion of phonon coupling is necessary for a proper description of the low-energy pygmy resonances and the corresponding transition densities for A < 132 nuclei, while in the A > 132 region the influence of phonon coupling is significantly smaller. The radiative neutron capture cross sections leading to the stable 124 Sn and unstable 132 Sn and 150 Sn nuclei are calculated with both the (Q)RPA and the beyond-(Q)RPA strength functions and shown to be sensitive to both the predicted low-lying strength and the phonon-coupling contribution. The comparison with the widely used phenomenological generalized Lorentzian approach shows considerable differences both for the strength function and the radiative neutron capture cross section. In particular, for the neutron-rich 150 Sn, the reaction cross section is found to be increased by a factor greater than 20. We conclude that the present approach may provide a complete and coherent description of the γ -ray-strength function for astrophysics applications. In particular, such calculations are highly recommended for a reliable estimate of the electromagnetic properties of exotic nuclei.

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“…The recommended rates in the BRUSLIB library correspond to TALYS calculations performed with the parametrized nuclear potential given in [26], NLD from the combinatorial model of Ref. [34] and γ-ray strengths calculated using the Hartree-Fock-Bogolyubov methods [44].…”

Section: Discussionmentioning

confidence: 99%

Proton capture cross section ofGe72and astrophysical implications

et al. 2015

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University of Notre Dame using a 1.8 to 3.6 MeV proton beam. In order to test the predictive power of different theoretical calculations in the region, experimental values are compared to the results given by the nuclear reaction code TALYS 1.6. The theoretical uncertainties in the cross section arising from different combinations of nuclear level densities, γ-ray strength functions and optical model potentials were reduced to 10 − 18% by the experimental data. The recommended reaction rates from the standard astrophysical libraries, BRUSLIB and REACLIB, are found to be in good agreement with the experimental results.

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Microscopic HFB + QRPA predictions of dipole strength for astrophysics applications

Cited by 285 publications

References 40 publications

Temperature-dependent combinatorial level densities with the D1M Gogny force

Temperature-dependent combinatorial level densities with the D1M Gogny force

Self-consistent calculations of the strength function and radiative neutron capture cross section for stable and unstable tin isotopes

Proton capture cross section ofGe72and astrophysical implications

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