Observation of Giant Dipole Resonances Built on States of High Energy and Spin

Newton, J.O.; Herskind, B.; Diamond, R. M.; Dines, E.L.; Draper, J. E.; Lindenberger, K. H.; Schuck, Carsten; Shih, Sheng-Min; Stephens, F. S.

doi:10.1103/physrevlett.46.1383

Cited by 224 publications

(57 citation statements)

References 5 publications

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“…Since that time, many experimental data have become available from a wide range of events, together with an extensive theoretical investigation. Forty years after the first observation, evidences of finite temperature dipole modes taking place in a compound system from a heavy-ion collision, were also found [79]. As known, some features of the GDR vary with temperature (like the size of the deformation and the width), while the centroid energies tend to remain stable.…”

Section: Resultsmentioning

confidence: 90%

Unrestricted Skyrme-tensor time-dependent Hartree-Fock model and its application to the nuclear response from spherical to triaxial nuclei

2012

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The nuclear time-dependent Hartree-Fock model formulated in the three-dimensional space, based on the full standard Skyrme energy density functional complemented with the tensor force, is presented for the first time. Full self-consistency is achieved by the model. The application to the isovector giant dipole resonance is discussed in the linear limit, ranging from spherical nuclei ( 16 O, 120 Sn) to systems displaying axial or triaxial deformation ( 24 Mg, 28 Si, 178 Os, 190 W , 238 U). Particular attention is paid to the spin-dependent terms from the central sector of the functional, recently included together with the tensor. They turn out to be capable of producing a qualitative change on the strength distribution in this channel. The effect on the deformation properties is also discussed. The quantitative effects on the linear response are small and, overall, the giant dipole energy remains unaffected. Calculations are compared to predictions from the (quasi)-particle random phase approximation and experimental data where available, finding good agreement.

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Section: Resultsmentioning

confidence: 90%

Unrestricted Skyrme-tensor time-dependent Hartree-Fock model and its application to the nuclear response from spherical to triaxial nuclei

2012

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“…Many other resonances have been discovered [11,12]. In particular Giant Resonances have been observed in hot nuclei formed by fusion [13,14]. This demonstrates the survival of ordered vibrations in very excited systems, which are known to be chaotic, even if some Giant Resonance characteristics like the width are affected by the temperature [15,16].…”

Section: Introductionmentioning

confidence: 99%

Fusion process studied with a preequilibrium giant dipole resonance in time-dependent Hartree-Fock theory

2007

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The equilibration of macroscopic degrees of freedom during the fusion of heavy nuclei, like the charge and the shape, are studied in the Time-Dependent Hartree-Fock theory. The preequilibrium Giant Dipole Resonance (GDR) is used to probe the fusion path. It is shown that such isovector collective state is excited in N/Z asymmetric fusion and to a less extent in mass asymmetric systems. The characteristics of this GDR are governed by the structure of the fused system in its preequilibrium phase, like its deformation, rotation and vibration. In particular, we show that a lowering of the preequilibrium GDR energy is expected as compared to the statistical one. Revisiting experimental data, we extract an evidence of this lowering for the first time. We also quantify the fusion-evaporation enhancement due to γ-ray emission from the preequilibrium GDR. This cooling mechanism along the fusion path may be suitable to synthesize in the future super heavy elements using radioactive beams with strong N/Z asymmetries in the entrance channel.

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“…This GDR was investigated with several probes [2] and was also observed on top of highly excited states, e.g., in hot nuclei [5]. The survival of ordered motion in hot nuclei, i.e., in a chaotic environment, is one of the most striking phenomena in nuclear physics.…”

Section: Introductionmentioning

confidence: 99%

Couplings between dipole and quadrupole vibrations in tin isotopes

Simenel¹,

Chomaz²

2009

Phys. Rev. C

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We study the couplings between collective vibrations such as the isovector giant dipole and isoscalar giant quadrupole resonances in tin isotopes in the framework of the time-dependent Hartree-Fock theory with a Skyrme energy density functional. These couplings are a source of anharmonicity in the multiphonon spectrum. In particular, the residual interaction is known to couple the isovector giant dipole resonance with the isoscalar giant quadrupole resonance built on top of it, inducing a nonlinear evolution of the quadrupole moment after a dipole boost. This coupling also affects the dipole motion in a nucleus with a static or dynamical deformation induced by a quadrupole constraint or boost respectively. Three methods associated with these different manifestations of the coupling are proposed to extract the corresponding matrix elements of the residual interaction. Numerical applications of the different methods to 132 Sn are in good agreement with each other. Finally, several tin isotopes are considered to investigate the role of isospin and mass number on this coupling. A simple 1/A dependence of the residual matrix elements is found with no noticeable contribution from the isospin. This result is interpreted within the Goldhaber-Teller model.

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Observation of Giant Dipole Resonances Built on States of High Energy and Spin

Cited by 224 publications

References 5 publications

Unrestricted Skyrme-tensor time-dependent Hartree-Fock model and its application to the nuclear response from spherical to triaxial nuclei

Unrestricted Skyrme-tensor time-dependent Hartree-Fock model and its application to the nuclear response from spherical to triaxial nuclei

Fusion process studied with a preequilibrium giant dipole resonance in time-dependent Hartree-Fock theory

Couplings between dipole and quadrupole vibrations in tin isotopes

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