Proton pygmy resonances: Predictions for N = 20 isotones

Kim, Y.; Papakonstantinou, P.

doi:10.1140/epja/i2016-16176-0

Cited by 3 publications

(4 citation statements)

References 51 publications

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“…This was shown in Ref. [22] via a comparison between the stable Ca isotopes and their (mostly unstable) N=20 mirror isotones. Ca isotopes are excited weakly in terms of B(E1) below 9 MeV and do not show any evidence of skin modes.…”

Section: Pygmy Dipole Strength and Exotic Nucleimentioning

confidence: 73%

“…Ca isotopes are excited weakly in terms of B(E1) below 9 MeV and do not show any evidence of skin modes. Proton-rich N=20 isotones, on the other hand, are theoretically expected to be much more strongly excited and some of them (e.g., 46 Fe) to develop proton-skin modes [22]. The proton f 7/2 shell can be so loosely bound and spatially extended, that an extended proton density distribution can indeed develop.…”

Section: Pygmy Dipole Strength and Exotic Nucleimentioning

confidence: 99%

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Structures in the Nuclear Electric-Dipole Spectrum

Papakonstantinou¹

2017

Exotic Nuclei

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I undertake an anatomy of the nuclear electric-dipole spectrum and discuss selected observations. First, using data and calculations on 208 Pb as a representative case, I identify five conspicuous structures in the spectra of heavy nuclei: (1) the giant dipole resonance (GDR), (2) the dipole compression mode, (3) the isoscalar low-energy dipole mode (IS-LED), (4) the IS mode in the region of the GDR, and (5) a concentration of "pygmy" dipole strength (PDS) between the latter two. Next, compiling the data from Texas A&M I show that the energy of (4) follows roughly a A -1/6 dependence on the mass number. Finally, I summarize recent theoretical studies on the PDS in exotic nuclei, which suggest a strong influence of shell effects and loose binding.

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Section: Pygmy Dipole Strength and Exotic Nucleimentioning

confidence: 73%

Section: Pygmy Dipole Strength and Exotic Nucleimentioning

confidence: 99%

Structures in the Nuclear Electric-Dipole Spectrum

Papakonstantinou¹

2017

Exotic Nuclei

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“…Low-lying isoscalar and isovector dipole strength was investigated in Ref. [39] for 48 Ni and other N = 20 isotones. Larger amounts of E1 strength in the asymmetric N = 20 isotones were predicted than in their Z = 20 mirror nuclei.…”

Section: Introductionmentioning

confidence: 99%

Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model

Lyutorovich¹,

Tselyaev²,

Speth³

et al. 2018

Phys. Rev. C

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We explore giant resonance spectra and low-lying dipole strength in the Ni and Sn chains from proton rich to very neutron rich isotopes, relevant in astrophysical reaction chains. For the theoretical description we employ the random-phase approximation (RPA) plus many-body effects through a phonon coupling model with optimized selection of phonons. The nuclear force is based on the Skyrme-Hartree-Fock energy functional carried consistently through all steps of modelling. The main effect of phonon coupling is a broadening of the spectral distributions (collisional width). This broadening is particularly dramatic for low-lying dipole strength in very neutron rich nuclei delivering there a qualitative change of the spectra.

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“…[36], the authors explored the PDR in proton-rich Ar isotopes using the unitary correlator operator method. The shell model has also been used to study the PDR in proton-rich nuclei [37]. A continuum random-phase approximation (CRPA) was used to investigate the PDR states in N = 20 isotones [38].…”

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confidence: 99%

Isovector giant dipole resonances in proton-rich Ar and Ca isotopes *

Liu¹,

Liu²,

Shi-sheng³

et al. 2021

Chinese Phys. C

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The isovector giant dipole resonances (IVGDR) in proton-rich Ar and Ca isotopes have been systematically investigated using the resonant continuum Hartree-Fock+BCS (HF+BCS) and quasiparticle random phase approximation (QRPA) methods. The Skyrme SLy5 and density-dependent contact pairing interactions are employed in the calculations. In addition to the giant dipole resonances at energy around 18 MeV, pygmy dipole resonances (PDR) are found to be located in the energy region below 12 MeV. The calculated energy-weighted moments of PDR in nuclei close to the proton drip-line exhaust about 4% of the TRK sum rule. The strengths decrease with increasing mass number in each isotopic chain. The transition densities of the PDR states show that motions of protons and neutrons are in phase in the interiors of nuclei, while the protons give the main contribution at the surface. By analyzing the QRPA amplitudes of proton and neutron 2-quasiparticle configurations for a given low-lying state, we find that only a few proton configurations give significant contributions. They contribute about 95% to the total QRPA amplitudes, which indicates that the collectivity of PDR states is not strong in proton-rich nuclei in the present study.

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Proton pygmy resonances: Predictions for N = 20 isotones

Cited by 3 publications

References 51 publications

Structures in the Nuclear Electric-Dipole Spectrum

Structures in the Nuclear Electric-Dipole Spectrum

Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model

Isovector giant dipole resonances in proton-rich Ar and Ca isotopes *

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