Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes

Guttormsen, M.; Alhassid, Y.; Ryssens, Wouter; Ay, K. O.; Özgür, Mustafa; Algin, E.; Larsen, A. C.; Garrote, F. L. Bello; Dahl-Jacobsen, T.; Görgen, A.; Hagen, T. W.; Ingeberg, V. W.; Kheswa, B. V.; Klintefjord, M.; Midtbø, J. E.; Modamio, V.; Renstrøm, T.; Şahin, E.; Siem, S.; Tveten, G. M.; Zeiser, F.

doi:10.1016/j.physletb.2021.136206

Cited by 14 publications

(13 citation statements)

References 41 publications

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“…where σ 2 d is determined from known discrete levels at low excitation energy E = E d and σ 2 (S n ) is determined from the rigid-body moment of inertia (RMI) estimate, as shown in our previous work [12].…”

Section: Experiments and The Oslo Methodsmentioning

confidence: 99%

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Evolution of the γ -ray strength function in neodymium isotopes

Guttormsen¹,

Ay²,

Özgür³

et al. 2022

Phys. Rev. C

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The experimental γ -ray strength functions (γ SFs) of 142,[144][145][146][147][148][149][150][151] Nd have been studied for γ -ray energies up to the neutron separation energy using the Oslo method. The results represent a unique set of γ SFs for an isotopic chain with increasing nuclear deformation. The data reveal how the low-energy enhancement, the scissors mode, and the pygmy dipole resonance evolve with nuclear deformation and mass number. This indicates that the mechanisms behind the low-energy enhancement and the scissors mode are decoupled from each other.

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Section: Experiments and The Oslo Methodsmentioning

confidence: 99%

“…Since both experimental and theoretical studies of the NLD in the neodymium isotopes were recently published [12], we focus mainly on the γ SF in the present work.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the γ -ray strength function in neodymium isotopes

Guttormsen¹,

Ay²,

Özgür³

et al. 2022

Phys. Rev. C

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“…Figure 4: Total level density ρ(E x ) in 144 Nd and 148 Nd (top); our predictions depicted by the red line are compared to experimental data from low energy levels and n-capture resonance spacings [74,79] (marked in blue). The black data points stem from proton-photon coincidence yields observed at the UiOcyclotron [80]; they were normalized to the other data.…”

Section: Level and State Densitiesmentioning

confidence: 99%

“…For a comparison to experimental data in dependence of E x we use 144 Nd and 148 Nd for which a recent theoretical study [31] predicted broken axiality. For these isotopes experimental level density information was derived at the Oslo cyclotron [80] from coincident yields of photons cascading down from excited states of known energy. A regard of such data from photon yields justifies our use of the CTM below E pt [81].…”

Section: Level and State Densitiesmentioning

confidence: 99%

Broken axial symmetry as essential feature for a consistent modelling of various observables in heavy nuclei

Grosse¹,

Junghans²

2022

Preprint

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Although most nuclear spectroscopy as well as atomic hyperfine structure data do not deliver accurate information on nuclear axiality the ad-hoc assumption of symmetry about one axis found widespread use in nuclear model calculations. In the theoretical interpretation of nuclear properties as well as in the analysis of experimental data triaxiality was considered -if at all -only for some, often exotic, nuclides. A breaking of axial symmetry combined to a spin-independent moment of inertia results in a surprisingly simple heuristic triaxial parametrization of the yrast sequence in all heavy nuclei, including well deformed ones. No additional fit parameters are needed in detailed studies of the mass and charge dependence of the electric dipole strength in the range of and outside of giant dipole resonances. Allowing triaxiality also avoids the introduction of an arbitrary level density parameter ã to fit the accurate values observed in n-capture experiments and ã can be taken from nuclear matter studies. A combination of this value to the yrast energies no longer based on axiality and the related I(I+1) rule results in agreement to data independent of spin. And predictions for radiative neutron capture as derived on the basis of non-axiality are improved as well. The experimentally favoured broken axial symmetry is in accord to HFB and MC-shell model calculations already for nuclei in the valley of stability.

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“…The (Z − Z 0 ) dependence of the level densities may be quite sensitive to the single-particle energies which may change drastically as one moves away from the β-stability line. Consequently, the other microscopic effects such as collective enhancement due to rotational and vibrational states [21][22][23][24][25][26][27][28][29], pairing and shell corrections [30][31][32][33][34][35][36] will also be crucial in determining the behavior of level density around Z 0 [12,21,37]. One of the ways to include various microscopic effects in the level density parameter is through the semi-classical approach.…”

Section: Introductionmentioning

confidence: 99%

Nuclear level densities away from line of $β$-stability

Ghosh,

Maheshwari,

Saxena

et al. 2021

Preprint

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The variation of total nuclear level densities (NLDs) and level density parameters with proton number (Z) are studied around the β-stable isotope, Z 0 , for a given mass number. We perform our analysis for a mass range A = 40 to 180 using the NLDs from popularly used databases obtained with the singleparticle energies from two different microsopic mass-models. These NLDs which include microscopic structural effects such as collective enhancement, pairing and shell corrections, do not exhibit inverted parabolic trend with a strong peak at Z 0 as predicted earlier. We also compute the NLDs using the singleparticle energies from macroscopic-microscopic mass-model. Once the collective and pairing effects are ignored, the inverted parabolic trends of NLDs and the corresponding level density parameters become somewhat visible. Nevertheless, the factor that governs the (Z − Z 0 ) dependence of the level density parameter, leading to the inverted parabolic trend, is found to be smaller by an order of magnitude. We further find that the (Z − Z 0 ) dependence of NLDs is quite sensitive to the shell effects.

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Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes

Cited by 14 publications

References 41 publications

Evolution of the γ -ray strength function in neodymium isotopes

Evolution of the γ -ray strength function in neodymium isotopes

Broken axial symmetry as essential feature for a consistent modelling of various observables in heavy nuclei

Nuclear level densities away from line of $β$-stability

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