scholarly journals Electric dipole strength below the giant dipole resonance

2002 ◽  
Author(s):  
P. Mohr ◽  
T. Hartmann ◽  
K. Vogt ◽  
S. Volz ◽  
A. Zilges
Keyword(s):  
Electric Dipole ◽  
Giant Dipole Resonance ◽  
Dipole Strength ◽  
Dipole Resonance

Effect of Core Excitations on 29Si and on the Giant Dipole Resonance in 28Si

1973 ◽  
Vol 51 (9) ◽  
pp. 988-992 ◽  
Author(s):  
I. P. Johnstone ◽  
B. Castel
Keyword(s):  
Satisfactory Agreement ◽  
Giant Dipole Resonance ◽  
Energy Levels ◽  
Transition Rates ◽  
Dipole Strength ◽  
Dipole Resonance ◽  
Spectroscopic Factors ◽  
Core Excitations

The structure of 29Si is studied in a model which couples a neutron onto low-lying core states of 28Si. Very satisfactory agreement is obtained for energy levels, E2 transition rates, and spectroscopic factors. The splitting of the 28Si dipole strength is then investigated using a particle–core and hole–core interaction derived from this 29Si study, and the effect of various approximations is examined.

scholarly journals Microscopic description of the pygmy dipole resonance in neutron-rich Ca isotopes

2018 ◽  
Vol 194 ◽  
pp. 04002
Author(s):  
N.N. Arsenyev ◽  
A.P. Severyukhin ◽  
V.V. Voronov ◽  
N.V. Giai
Keyword(s):  
Electric Dipole ◽  
Random Phase Approximation ◽  
Strength Function ◽  
Random Phase ◽  
Strength Distribution ◽  
Low Energy ◽  
Dipole Strength ◽  
Quasiparticle Random Phase Approximation ◽  
Dipole Resonance ◽  
Dipole Response

We study the effects of the phonon-phonon coupling on the low-energy electric dipole response within a microscopic model based on an effective Skyrme interaction. The finite rank separable approach for the quasiparticle random phase approximation is used. Choosing as an example the isotopic chain of Calcium, we show the ability of the method to describe the low-energy E1 strength distribution. With one and the same set of parameters we describe available experimental data for 48Ca and predict the electric dipole strength function for 50Ca.

PYGMY DIPOLE RESONANCES

2009 ◽  
Vol 18 (07) ◽  
pp. 1425-1451 ◽  
Author(s):  
S. KREWALD ◽  
J. SPETH
Keyword(s):  
Electric Dipole ◽  
Theoretical Treatment ◽  
Resonance Fluorescence ◽  
Dipole Strength ◽  
Open Problems ◽  
Coulomb Dissociation ◽  
Dipole Resonance ◽  
Theoretical Approaches ◽  
Nuclear Resonance Fluorescence ◽  
Emission Threshold

Electric dipole strength below the particle emission threshold both in stable nuclei and short-lived isotopes has received increasing interest due to its astrophysical impact. In analogy to the giant dipole resonance, this strength is commonly referred to as pygmy resonance. Coulomb dissociation of neutron-rich unstable isotopes and nuclear resonance fluorescence photon scattering have begun to provide systematic data on electric dipole strength in various isotope chains. We review the present state of the art of theoretical approaches and point out some open problems. We emphasize the necessity of a simultaneous theoretical treatment of the nucleon separation energies and the energetically low-lying dipole strength because the presently available data do not exclude a non-collective nature of the pygmy strength.

scholarly journals Particle?Hole Description of Dipole States in17O

1986 ◽  
Vol 39 (6) ◽  
pp. 871 ◽  
Author(s):  
JA Eden ◽  
YI Assafiri
Keyword(s):  
Cross Section ◽  
Electric Dipole ◽  
Giant Dipole Resonance ◽  
Residual Interaction ◽  
Dipole Resonance ◽  
Hole Model

The particle-hole model has been applied to the 170 nucleus to study the electric dipole states below the giant dipole resonance (GDR). Comparison is made with the most recent photonuclear data for this nucleus and an E 1 assignment for the observed strength at 15� 1 Me V in the photoproton cross section is discussed. The WMBH residual interaction used in this calculation produces more T> strength below the GDR than predicted in other calculations using the Tabakin, Soper or Kuo-Brown interactions.

Theoretical investigation of giant dipole resonance in 146−152Nd isotopes with QRPA

2020 ◽  
Vol 29 (07) ◽  
pp. 2050040
Author(s):  
Nilufer Demirci Saygı ◽  
Filiz Ertuğral Yamaç ◽  
Ali Kuliev
Keyword(s):  
Cross Section ◽  
Giant Dipole Resonance ◽  
Random Phase ◽  
Spherical Geometry ◽  
Strength Distribution ◽  
Text Structure ◽  
Photoabsorption Cross Section ◽  
Dipole Strength ◽  
Quasiparticle Random Phase Approximation ◽  
Dipole Resonance

We investigate the electric dipole ([Formula: see text]) structure properties of the deformed [Formula: see text]Nd nuclei in the giant dipole resonance (GDR) region within the framework of the quasiparticle random-phase approximation (QRPA). Translational and Galilean invariance (TGI) QRPA with separable isovector dipole–dipole residual interaction have been employed for the calculations. We have computed the photoabsorption cross-section and then we have compared with the experimental data. Our calculations revealed that while the photoabsorption cross-section shows a Lorentzian line in the neighborhood of spherical geometry, it starts to shift to an asymmetric shape by increasing deformation in [Formula: see text]Nd isotopes by increasing neutron number. In addition to this, we have also observed that the splitting of the [Formula: see text] strength distribution and the separation between [Formula: see text] and [Formula: see text] branches are increasing. We have calculated the contribution of the electric and magnetic parts of total dipole strength up to 20[Formula: see text]MeV for the nuclei of interest. This calculation shows that the electric part dominates the total dipole strength and [Formula: see text] excitation dominates the electric part.

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