Multiphonon vibrational states in deformed nuclei

Wu, Xiaofeng; Aprahamian, A.; Fischer, Susan M.; Reviol, W.; Liu, G.; Saladin, J.X.

doi:10.1103/physrevc.49.1837

Cited by 53 publications

(35 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…PACS: 21.60. Cs, 21.10.Re, 21.10.Ky, 27.70.+q Recently two-phonon γγ-vibrational bands have been identified in a number of nuclei [1][2][3], where pronounced anharmonicities have been observed in the vibrational spectrum. A microscopic description of the energies and transition probabilities of two-phonon vibrational excitations remains a challenge to nuclear models.…”

mentioning

confidence: 99%

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

et al. 2002

Self Cite

View full text Add to dashboard Cite

The Triaxial Projected Shell Model (TPSM) has been successful in providing a microscopic description of the energies of multi-phonon vibrational bands in deformed nuclei. We report here on an extension of the TPSM to allow, for the first time, calculations of B(E2) values connecting γ-and γγ-vibrational bands and the ground state band. The method is applied to 166,168 Er. It is shown that most of the existing B(E2) data can be reproduced rather well, thus strongly supporting the classification of these states as γ-vibrational states. However, significant differences between the data and the calculation are seen in those B(E2) values which involve odd-spin states of the γ-band. Understanding these discrepancies requires accurate experimental measurements and perhaps further improvements of the TPSM. PACS: 21.60. Cs, 21.10.Re, 21.10.Ky, 27.70.+q Recently two-phonon γγ-vibrational bands have been identified in a number of nuclei [1][2][3], where pronounced anharmonicities have been observed in the vibrational spectrum. A microscopic description of the energies and transition probabilities of two-phonon vibrational excitations remains a challenge to nuclear models. The Triaxial Projected Shell Model [4,5] is a new microscopic, fully quantum-mechanical model with a unified treatment of the vibrational and rotational states. In the TPSM approach, one introduces triaxiality in the deformed basis and performs exactly three-dimensional angular momentum projection [4]. In this way, the deformed vacuum state is much enriched by allowing all possible Kcomponents. Diagonalization mixes these components, and various excited bands emerge [5] besides the ground state (g.s.) band (K = 0). The excited K = 2 band describes the one-phonon γ-vibrational band; and the excited band with K = 4 accounts for the two-phonon γγ-band. The observed anharmonicities in the energies of multi-phonon vibrational bands occur quite naturally from the TPSM without including additional ingredients in the model [5]. The TPSM has recently been applied also to the study of transition quadrupole moments in the g.s. bands of γ-soft nuclei and the magnetic dipole properties of the γ-vibrational states [6,7]. However, inband and inter-band E2-transitions, which are important quantities in supporting classification of states, have not been studied yet.The purpose of this paper is to report a new extension of the TPSM which allows the calculation of B(E2) values for transitions connecting the g.s. band, the single γ, and double γγ vibrational bands. We have searched the entire rare-earth region for experimental inter-band B(E2) values that allow a comparison with our calculations. Data on absolute B(E2) values are sparse and only in few cases they are known for more than one or two members of the γ-band. In this paper we study B(E2) values for 166,168 Er, which are the best cases. These nuclei exhibit well established double-phonon excitations [2,3].168 Er is one of the most extensively studied nuclei in this mass region with several measured B(E2) value...

show abstract

mentioning

confidence: 99%

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

et al. 2002

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the far right-hand-side of Fig. 2, the expectation value of K 2 is indicated for the case of complete mixing, that is, if all the diagonalization coefficients have the same 1 √ d * Recently the K=4 band received some attention through a systematic measurement of γ-vibrational anharmonicities in the rare-earth region [23,24] magnitude and thus ARM|K 2 |ARM y = It is now interesting to use these simple results as a backdrop for a study of pairing induced K-band mixing in the pseudo-SU(3) model. To accomplish this it is necessary to have a shell-model expression for theK 2 operator [13,14,26].…”

Section: Figurementioning

confidence: 99%

Effects of pairing in the pseudo-SU(3) model

1995

View full text Add to dashboard Cite

An extended version of the pseudo-SU(3) model which includes both spin and proton-neutron degrees of freedom is used to study the influence of the pairing interaction on K-band mixing, B(E2) values and quadrupole moments. Using the asymmetric rotor model as a backdrop, specific consequences of a many-particle shell-model based description of these collective properties are demonstrated and fundamental limits of the collective model's approach are investigated. Finally, the pseudo-SU(3) model, including representation mixing induced by pairing, is used to calculate the energies of 140 Ce and the results are compared to experimental data and other theories.

show abstract

“…Vibrational spectra can, in principle, be constructed from one or more quanta of these states resulting in two-phonon ββ ( wide ranges in energy anharmonicities [11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Lifetime measurements in Dy162

et al. 2017

Self Cite

View full text Add to dashboard Cite

Background: The nature of oscillations or excitations around the equilibrium deformed nuclear shape remains an open question in nuclear structure. The 162 Dy nucleus is one of the most extensively studied nuclei with the (n, γ), (n, e − ), (α,2n) reactions and most recently the (p, t) pickup reaction adding eleven 0 + states up to an excitation energy of 2.8 MeV to an already well developed level scheme. However, a major shortfall for a better understanding of the nature of the plethora of bands and levels in this nucleus has been the lack of lifetime measurements.

show abstract

Multiphonon vibrational states in deformed nuclei

Cited by 53 publications

References 31 publications

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

Effects of pairing in the pseudo-SU(3) model

Lifetime measurements in Dy162

Contact Info

Product

Resources

About