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The structure of the isovector dipole resonance in neutron-rich calcium isotope, $^{60}Ca$, has been investigated by implementing a careful treatment of the differences of neutron and proton radii in the continuum random phase approximation…

Nuclear Theory · Physics 2007-05-23 T. N. Leite , N. Teruya

New experimental data on the neutron single-particle character of the Pygmy Dipole Resonance (PDR) in $^{208}$Pb are presented. They were obtained from $(d,p)$ and resonant proton scattering experiments performed at the Q3D spectrograph of…

The centroid, width and percentage of energy weighted sum rule of dipole resonances can be strongly affected by dynamical fluctuations and static deformations of the nuclear surface, deformations and fluctuations which, in turn, depend on…

Nuclear Theory · Physics 2019-09-04 R. A. Broglia , F. Barranco , A. Idini , G. Potel , E. Vigezzi

Electric dipole strength near the neutron separation energy significantly impacts nuclear structure properties and astrophysical scenarios. These excitations are complex in nature and may involve the so-called pygmy dipole resonance (PDR).…

Nuclear Theory · Physics 2025-02-12 Eun Jin In , Emanuel Chimanski , Jutta Escher , Sophie Péru , Aaina Thapa , Walid Younes

Pygmy and Giant Dipole Resonance (PDR and GDR) in Ni isotopes have been investigated by Coulomb excitation in the framework of the Isospin-dependent Quantum Molecular Dynamics model (IQMD). The spectra of $\gamma$ rays are calculated and…

Nuclear Theory · Physics 2013-02-04 C. Tao , Y. G. Ma , G. Q. Zhang , X. G. Cao , D. Q. Fang. H. W. Wang

An unexpected enhancement in the $\gamma$-ray strength function, as compared to the low energy tail of the Giant Dipole Resonance (GDR), has been observed for Sc, Ti, V, Fe and Mo isotopes for $E_\gamma<4$ MeV. This enhancement was not…

Motivated by arguments of the nuclear core-layer model formulated in [S.I. Bastrukov, J.A. Maruhn, Z.Phys. A 335 (1990) 139], the macroscopic excitation mechanism of electric pygmy dipole resonance (PDR) is considered as owing its origin to…

Nuclear Theory · Physics 2011-03-28 S. I. Bastrukov , I. V. Molodtsova , S. Misicu , H-K. Chang , D. V. Podgainy

To complete earlier studies of the properties of the electric pygmy dipole resonance (PDR) obtained in various nuclear reactions, the excitation of the 1$^-$ states in $^{140}$Ce by $(e,e')$ scattering for momentum transfers…

Nuclear Theory · Physics 2020-01-08 V. Yu. Ponomarev , D. H. Jakubassa-Amundsen , A. Richter , J. Wambach

Microscopic structure of the low-lying isovector dipole excitation mode in neutron-rich $^{26,28,30}$Ne is investigated by performing deformed quasiparticle-random-phase-approximation (QRPA) calculations. The particle-hole residual…

Nuclear Theory · Physics 2008-11-26 Kenichi Yoshida , Nguyen Van Giai

The $\alpha$ ($^4$He) - clustering structure is a common phenomenon in light nuclei due to the decreasing contribution of mean field in few-body system. In this work we presented calculations of giant dipole resonance (GDR) excitations for…

Nuclear Theory · Physics 2021-09-21 Bo-Song Huang , Yu-Gang Ma

Low-energy dipole excitations have been investigated theoretically in N=50, several N=82 isotones and the Z=50 Sn isotopes. For this purpose a method incorporating both HFB and multi-phonon QPM theory is applied. A concentration of…

Nuclear Theory · Physics 2008-11-26 N. Tsoneva , H. Lenske

A very important open question related to the pygmy dipole resonance is about its quite elusive collective nature. In this paper, within a harmonic oscillator shell model, generalizing an approach introduced by Brink, we first identify the…

Nuclear Theory · Physics 2015-06-03 V. Baran , B. Frecus , M. Colonna , M. Di Toro

The $^{112,120}$Sn$(\gamma,\gamma')$ reactions have been studied at the S-DALINAC. Electric dipole (E1) strength distributions have been determined including contributions from unresolved strength extracted by a fluctuation analysis.…

The electric dipole excitation of various nuclei is calculated with a Random Phase Approximation phenomenological approach. The evolution of the strength distribution in various groups of isotopes, oxygen, calcium, zirconium and tin, is…

Nuclear Theory · Physics 2009-08-18 G. Co' , V. De Donno , C. Maieron , M. Anguiano , A. M. Lallena

The evolution of the PDR strength with the neutron excess is investigated in Sn isotopic and N=82 isotonic chains with regard to its possible connection with the neutron skin thickness. For this purpose a recently proposed method…

Nuclear Theory · Physics 2008-11-26 N. Tsoneva , H. Lenske

The isotopic dependence of the excitation energies of the pygmy dipole resonance (PDR) is analyzed in the framework of the self-consistent relativistic Hartree-Bogoliubov (RHB) model and the relativistic quasiparticle random-phase…

Nuclear Theory · Physics 2011-07-19 N. Paar , T. Niksic , D. Vretenar , P. Ring

Coulomb excitation of the exotic neutron-rich nucleus Ne26 on a Pb208 target was measured at 58 MeV/u in order to search for low-lying E1 strength above the neutron emission threshold. This radioactive beam experiment was carried out at the…

Proton decay from the 3$\hbar\omega$ isoscalar giant dipole resonance (ISGDR) in $^{58}$Ni has been measured using the ($\alpha,\alpha'p$) reaction at a bombarding energy of 386 MeV to investigate its decay properties. We have extracted the…

The information on pygmy resonances reveals new aspects on the isospin dynamics of the nucleus with important astrophysical consequences. In this connection, the precise knowledge of nuclear response functions plays a key role in the…

Nuclear Theory · Physics 2015-06-12 Nadia Tsoneva , Horst Lenske

Systematic studies of dipole and other multipole excitations in stable and exotic nuclei are discussed theoretically. Exploring the relation of the strengths of low-energy dipole and quadrupole pygmy resonances to the thickness of the…

Nuclear Theory · Physics 2015-05-18 N. Tsoneva , H. Lenske