On the nature of low-lying electric dipole excitations in light and heavy deformed nuclei

Guhr, T.; Hummel, K.D.; Kilgus, G.; Bohle, D.; Richter, A.; Jager, C. W. de; Vries, H. de; Huberts, P.K.A. de Witt

doi:10.1016/0375-9474(89)90566-6

Cited by 34 publications

(7 citation statements)

References 27 publications

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“…In both rare-earth and actinide nuclei, there is a large number of R exp values between 1 2 and 2. This is evidence of K mixing, which is known to increase in regions of large level density [39].…”

Section: Resultsmentioning

confidence: 89%

Dipole response of238U to polarized photons below the neutron separation energy

et al. 2012

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Nuclear resonance fluorescence experiments were carried out at the High-Intensity γ -ray Source facility at Triangle Universities Nuclear Laboratory to characterize the low-energy dipole structure of 238 U using 100% linearly polarized photon beams from 2.0 to 6.2 MeV. 113 transitions corresponding to de-excitations to the ground state in 238 U were observed and the energy, spin, parity, integrated cross section, reduced width, and branching ratio were determined for each of these identified levels. The total E1 γ -ray interaction cross section was calculated and it was deduced that the observed concentration of low-lying E1 transitions were excited from the low-energy tail of the giant dipole resonance and were not a pygmy dipole resonance. Comparisons were made between quasiparticle random-phase approximation calculations and the experimentally observed strength. The observed and predicted M1 strength agreed well with each other. However, there was no similar agreement for the E1 strength.

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Section: Resultsmentioning

confidence: 89%

Dipole response of238U to polarized photons below the neutron separation energy

et al. 2012

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“…These low-lying 1 − states do not originate from the ph excitations building up the GDR. The experimental analysis [2,[139][140][141][142][143][144][145][146][147] has established that they have a more complex structure.…”

Section: Low-lying Negative Parity Dipole Excitationsmentioning

confidence: 99%

Low-energy nuclear spectroscopy in a microscopic multiphonon approach

Iudice

Ponomarev

Stoyanov

et al. 2012

J. Phys. G: Nucl. Part. Phys.

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The low-lying spectra of heavy nuclei are investigated within the quasiparticlephonon model. This microscopic approach goes beyond the quasiparticle random-phase approximation by treating a Hamiltonian of separable form in a microscopic multiphonon basis. It is therefore able to describe the anharmonic features of collective modes as well as the multiphonon states, whose experimental evidence is continuously growing. The method can be put in close correspondence with the proton-neutron interacting boson model. By associating the microscopic isoscalar and isovector quadrupole phonons with proton-neutron symmetric and mixed-symmetry quadrupole bosons, respectively, the microscopic states can be classified, just as in the algebraic model, according to their phonon content and their symmetry. In addition, these states disclose the nuclear properties which are to be ascribed to genuine shell effects, not included in the algebraic approach. Due to its flexibility, the method can be implemented numerically for systematic studies of spectroscopic properties throughout entire regions of vibrational nuclei. The spectra and multipole transition strengths so computed are in overall good agreement with the experimental data. By exploiting the correspondence of the method with the interacting boson model, it is possible to embed the microscopic states into this algebraic frame and, therefore, face the study of nuclei far from shell closures, not directly accessible to merely microscopic approaches. Here, it is shown how this task is accomplished through systematic investigations of magnetic dipole and, especially, electric dipole modes along paths moving from the vibrational to the transitional regions. The method is very well suited to the study of well-deformed nuclei. It provides reliable descriptions of low-lying

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“…The 3062.0-keV level was also observed in the experiment described in Ref. [40] and in an electron inelastic scattering experiment on 48 Ti [41]. For this level J π = 2 + was assigned from a model-independent plane-wave Born approximation (PWBA) analysis of the angular distribution.…”

Section: Theoretical Considerationsmentioning

confidence: 71%

Neutron inelastic scattering measurements on the stable isotopes of titanium

et al. 2017

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The results of a neutron inelastic scattering experiment performed at the Geel Electron Linear Accelerator pulsed white neutron source of the European Commission Joint Research Centre are reported. The neutrons with energies up to 18 MeV interacted with a nat Ti sample and the γ rays resulting from inelastic scattering reactions on the stable isotopes were detected using the Gamma Array for Inelastic Neutron Scattering (GAINS) spectrometer. We were able to measure the γ -production cross sections for 21 transitions in the five stable Ti isotopes. From these, the level cross sections and the total inelastic cross sections were determined. Our experimental results are compared with theoretical calculations performed using the TALYS 1.8 code, evaluated nuclear data libraries, and also with previously reported results.

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On the nature of low-lying electric dipole excitations in light and heavy deformed nuclei

Cited by 34 publications

References 27 publications

Dipole response of238U to polarized photons below the neutron separation energy

Dipole response of238U to polarized photons below the neutron separation energy

Low-energy nuclear spectroscopy in a microscopic multiphonon approach

Neutron inelastic scattering measurements on the stable isotopes of titanium

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