Strong correlation and saturation of<i>E</i>2 and<i>M</i>1 transition strengths in even-even rare-earth nuclei

Rangacharyulu, C.; Richter, A.; Hj, Wörtche; Ziegler, W.; Rf, Casten

doi:10.1103/physrevc.43.r949

Cited by 79 publications

(44 citation statements)

References 18 publications

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“…Subsequent experiments were able to confirm the existence of the mode in three regions of the nuclear table, i.e., the deformed rare-earth nuclei, the fp-shell nuclei and the actinides. Its absence in (p, p ) reactions provided a strong evidence in favour of the orbital nature of the mode, while joint (e, e ) and (γ, γ ) experiments [24] showed that the mode is fragmented into several peaks closely packed around a prominent one with a total strength B(M 1) ↑≈ 3µ 2 N that grows quadratically with the deformation parameter [173] and is proportional to the strength of the E2 transition to the lowest 2 + state [120]. The main features extracted from several review articles on the experimental status can be summarized as:…”

Section: Nature Of Low-lying M1 Excitationsmentioning

confidence: 98%

Relativistic quasiparticle random phase approximation in deformed nuclei

Arteaga

Ring

2007

Progress in Particle and Nuclear Physics

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Covariant density functional theory is used to analyse the response to the E1 and M1 electromagnetic transition operators in superfluid deformed nuclei in the framework of self-consistent Hartree-Bogoliubov theory and relativistic quasiparticle random phase (RQRPA) approximation. The fully self-consistent RHB+RQRPA equations are posed for the case of axial symmetry and for three different kinds of energy functionals, and solved with the help of a new parallel code. Special care is taken in order to validate the proper decoupling of spurious modes. Results of the first multipole magnetic operator (M1) response in light and heavy deformed nuclei are presented and analysed; in particular, the scissors mode and spin excitations. Qualitative agreement with experiment is obtained for the position of the scissors mode, and its structure as a rotation of the deformed neutron density against the deformed proton density reproduced. In addition to the scissors mode, a soft M1 mode with strong orbital character is found in heavy nuclei at relatively low energies. From the analysis of the proton and neutron transition densities in the intrinsic frame, and from the structure of the RQRPA amplitudes, it is concluded that this mode corresponds to a collective rotation of the deformed neutron skin against the deformed proton-neutron core. The response in light and heavy nuclei to the electric dipole operator (E1) is also given consideration. The position of the Giant Dipole Resonance is well reproduced within the RHB+RQRPA framework in axial symmetry. The effects of superfluidity and deformation on the Pygmy Dipole Resonance are closely examined. Excellent agreement with recent experimental results is found. v vi AcknowledgementsFirst and foremost I would like to thank my supervisor, Prof. Dr. Peter Ring, not only for stimulating discussions and timely advice, but also for his support throughout the various phases of the work presented in this document. His understanding and experience in many areas has made a pleasure working with him. I am particularly grateful for his optimism and overall confidence in the project, always trying to point me on the right direction but giving me enough leeway to learn from my own mistakes.Many thanks go to Roger Hilton, who was always a source of good humour and interesting conversations while at the TUM. He patiently read the first drafts and helped me polish all the rough edges, both in the contents and in the use of the English language.It is a pleasure for me to thank all my colleagues at the TUM Theory Department and at the TUM campus in Garching, who have provided support and company during my time in Munich, with a special mention to

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Section: Nature Of Low-lying M1 Excitationsmentioning

confidence: 98%

Relativistic quasiparticle random phase approximation in deformed nuclei

Arteaga

Ring

2007

Progress in Particle and Nuclear Physics

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“…The 1 + mode is expected to be dominantly excited by the isovector part of the M1 operator indicating its isovector character. The large M1 transition strength and its close correlation [23][24][25][26] to the collective E2 excitation strength in deformed nuclei is usually considered an indication of the collective nature of the 1 + sc state. Another state with spin different from J π = 1 + but of similar isovector character, the one-quadrupole phonon 2 + ms state, has been identified from M1 strengths, too.…”

Section: Introductionmentioning

confidence: 99%

Shell model description of “mixed-symmetry” states in Mo

et al. 2000

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Shell model calculations have been performed for the nucleus 94 Mo. The calculated excitation energies and electromagnetic properties of low-lying states are in good agreement with the data, which include states with mixedsymmetry (MS) assignments in previous Interacting Boson Model studies. In the shell model large isoscalar E2 matrix elements are found between states with MS assignments indicating that they form a class of states with similar proton-neutron symmetry.Typeset using REVT E X 1

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“…The top part of fig. 8 shows these sums 12 for the rare earth region and clearly demonstrates the very smooth behavior of the isovector collectivity as a function of P. Though this is perhaps not surprising, given the analytic expression for the B(M1) sum rule in the SU(3) limit of the IBM-2, it is nevertheless remarkable how smooth the behavior actually is. What is even more revealing, however, is the comparison with B(E2) strengths to the first 2+ state, shown for comparison in the upper part of the figure.…”

Section: The Npn N Schemementioning

confidence: 79%

The empirical residual proton-neutron interaction and the onset of collectivity in nuclei

Casten¹

1992

AIP Conference Proceedings

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DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United States Gover-icni. Neither the United States Government nor any agency thereof, nor any of their empljy . a , ->akes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. MASTER DISTRIBUTION OF THIS OOCWflHJT IS UNLIMITED THE EMPIRICAL RESIDUAL PROTON-NEUTRON INTERACTION AND THE ONSET OF COLLECTIVITY IN NUCLEIRichard F. Casten Brookhaven National Laboratory, Upton, New York, 11973, USA ABSTRACTThe critical role of the residual valence p-n interaction in the development and evolution of collectivity, and the onset of shape/phase transitions, is discussed from the standpoint of phenomenological approaches, the empirical extraction of individual p-n interaction strengths, and simple model calculations of them.

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Strong correlation and saturation ofE2 andM1 transition strengths in even-even rare-earth nuclei

Cited by 79 publications

References 18 publications

Relativistic quasiparticle random phase approximation in deformed nuclei

Relativistic quasiparticle random phase approximation in deformed nuclei

Shell model description of “mixed-symmetry” states in Mo

The empirical residual proton-neutron interaction and the onset of collectivity in nuclei

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