Level densities for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>20</mml:mn><mml:mo>&lt;~</mml:mo><mml:mi>A</mml:mi><mml:mo>&lt;~</mml:mo><mml:mn>110</mml:mn></mml:math>

Al-Quraishi, S. I.; Grimes, S. M.; Massey, T. N.; Resler, D.A.

doi:10.1103/physrevc.67.015803

Cited by 105 publications

(94 citation statements)

References 8 publications

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“…The empty circles (red color) present the low energy fit, around 1-5 MeV, while the filled circles (black color) present the standard 5-25 MeV energy range fit. We can see that at low energies the fitted level density parameter a is slightly larger, but still it is not large enough to be compared with the empirical estimates [52,53]. …”

Section: Thermodynamic Description and Comparison With Phenomenolmentioning

confidence: 97%

“…This is the known Rosenzweig effect [54] described by Ericson [17] as due to "a considerably larger number of rearrangement possibilities when the shell is half-filled". The empirical estimates for the same nuclei are available from the level density at the neutron resonances energy [52], which do not show considerable shell effects, and by extrapolation from low-lying levels [53] where one can see very weak shell effects in the region of the mass number around A ≈ 50. The Constant in Eq.…”

Section: Thermodynamic Description and Comparison With Phenomenolmentioning

confidence: 99%

“…In particular, these collision-like interactions are responsible for the formation of chaotic states with high information entropy and the process of thermalization [6]. For example, it was shown [49][50][51] that the exactly considered pairing interaction contains some chaotic fea- [52], red diamonds), and fit using experimental low-lying levels ( [53], yellow squares).…”

Section: Coherent and Incoherent Interactionsmentioning

confidence: 99%

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Nuclear level density: Shell-model approach

Sen'kov

Zelevinsky

2016

Phys. Rev. C

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The knowledge of the nuclear level density is necessary for understanding various reactions including those in the stellar environment. Usually the combinatorics of Fermi-gas plus pairing is used for finding the level density. Recently a practical algorithm avoiding diagonalization of huge matrices was developed for calculating the density of many-body nuclear energy levels with certain quantum numbers for a full shell-model Hamiltonian. The underlying physics is that of quantum chaos and intrinsic thermalization in a closed system of interacting particles. We briefly explain this algorithm and, when possible, demonstrate the agreement of the results with those derived from exact diagonalization. The resulting level density is much smoother than that coming from the conventional mean-field combinatorics. We study the role of various components of residual interactions in the process of thermalization, stressing the influence of incoherent collision-like processes. The shell-model results for the traditionally used parameters are also compared with standard phenomenological approaches.

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Section: Thermodynamic Description and Comparison With Phenomenolmentioning

confidence: 97%

Section: Thermodynamic Description and Comparison With Phenomenolmentioning

confidence: 99%

Section: Coherent and Incoherent Interactionsmentioning

confidence: 99%

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Nuclear level density: Shell-model approach

Sen'kov

Zelevinsky

2016

Phys. Rev. C

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“…However, the parity dependence at low excitation energies remains in question -the available level scheme [21] shows significant parity asymmetry below about 2.5 MeV. We attempted to check the results using a NLD with no asymmetry above 2.5 MeV, as well as for an asymmetry given by the dependence proposed in [27]. The same parameters of the parity dependence function as used in the analysis of MSC spectra of 96 Mo were adopted -∆ π = 3.2 MeV and C π = 1.0 MeV -see Ref.…”

Section: B Nuclear Level Density Modelsmentioning

confidence: 99%

Measurement of theMo97(n,γ)reaction with the DANCEγcalorimeter array

et al. 2015

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Spectra of γ rays following the 97 Mo(n, γ) reaction were measured as a function of incident neutron energy with the DANCE (Detector for Advanced Neutron Capture Experiments) array of 160 BaF2 scintillation detectors at the Los Alamos Neutron Science Center using an enriched 97 Mo target. These spectra were used for the assignment of spins of the 97 Mo resonances up to neutron energy En = 1.7 keV, as well as in the study of photon strength functions (PSFs) in 98 Mo. Analysis of the spectra with the nuclear statistical model showed that they can be well reproduced with the same PSF models which well described the γ decay following slow neutron capture in 95 Mo. On the other hand, the spectra are inconsistent with PSFs describing some other experimental data in 98 Mo.

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“…According to this, the level density is expected to decrease with increasing |T 3 |. Recently, the analysis of the level density data [7] for nuclei with 20 ≤ A ≤ 110 [8], [9] has been carried out comparing different isospin dependences. It has been shown that, compared to the prescription based on the N-Z dependence, a reduction factor of the level density based on the distance from the valley of stability Z-Zo, where Zo is the atomic number of the beta stable isotope with the same mass, provides a better description of data.…”

Section: Introductionmentioning

confidence: 99%

Search for isospin effects on nuclear level density

Brondi

Nitto

Rana

et al. 2010

EPJ Web of Conferences

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Abstract. Studies on the isospin dependence of the level density have been recently reported in the literature for nuclei with 20≤A≤110. Corrections to the level density have been deduced which would imply a significant reduction of this quantity for nuclei far from the valley of stability. Isospin effects on the level density are also expected through the symmetry energy contribution to the nuclear masses, which is predicted to increase with the temperature. According to these findings, we have implemented the statistical model in order to account for isospin effects on the level density parameter a and on the temperature-dependent symmetry energy. We present the results of calculations for the decay of a variety of neutron-rich composite systems. We found that isospin produces sizable effects on different observables, this result being promising for future experiments with the second generation RIB facilities SPES and SPIRAL2. We report the results of a first experiment aimed at searching for isospin effects in the decay of 139 Eu composite nuclei produced by a stable beam at E x =90 MeV.

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Level densities for20<~A<~110

Cited by 105 publications

References 8 publications

Nuclear level density: Shell-model approach

Nuclear level density: Shell-model approach

Measurement of theMo97(n,γ)reaction with the DANCEγcalorimeter array

Search for isospin effects on nuclear level density

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