Octupole shapes and shape changes at high spins in the<i>Z</i>≊58,<i>N</i>≊88 nuclei

Nazarewicz, W.; Tabor, S. L.

doi:10.1103/physrevc.45.2226

Cited by 98 publications

(74 citation statements)

References 42 publications

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“…The octupole interaction can be so strong that there exist nuclei having static reflection-asymmetric deformation, such as 224 Ra [1]. In addition, it has been found that rotation can stabilize octupole deformation [2][3][4].…”

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confidence: 99%

“…Calculations suggest that the *Corresponding author (email: frxu@pku.edu.cn) superdeformed minima are soft with respect to octupole deformations in A∼40, A∼150 and A∼190 mass regions [6][7][8]. This is because the single-particle spectrum at superdeformations favors octupole excitations due to the presence of intruder states [2]. Experiments have identified some octupolevibrational states and strong E1 transitions which are expected to connect these vibrational levels to the lowest SD band [7][8][9][10].…”

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confidence: 99%

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Investigation of octupole effects in superheavy nuclei with improved potential-energy-surface calculations

et al. 2012

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It has been found that high-order deformation (e.g. β 6 ) can have important effects on the structures of superheavy nuclei. In the present work, we investigate octupole deformation effects on superheavy nuclei with an improved potential-energy-surface (PES) calculation by including reflection-asymmetric deformations in a space of (β 2 , β 3 , β 4 , β 5 ). The calculations give various deformations including highly deformed (β 2 ≈ 0.4) and superdeformed (β 2 ≈ 0.7) shapes. The octupole-deformation degree of freedom mainly affects the fission barrier beyond the second minimum of PES. Experimentally, octupole correlation manifests itself in atomic nuclei usually with enhanced E1 transitions connecting interleaved positive and negative-parity bands, which is similar to the rotational bands observed in reflectionasymmetric molecules [1]. Such correlation originates from the coupling of a pair of single-particle orbitals close to the Fermi Surface and having ΔN = 1, Δl = 3 and Δ j = 3. superdeformed minima are soft with respect to octupole deformations in A∼40, A∼150 and A∼190 mass regions [6][7][8]. This is because the single-particle spectrum at superdeformations favors octupole excitations due to the presence of intruder states [2]. Experiments have identified some octupolevibrational states and strong E1 transitions which are expected to connect these vibrational levels to the lowest SD band [7][8][9][10].With the development of the radioactive beam facility, heavy-ion accelerator and highly-effective detector systems [11,12], great progress has been made recently in nuclear physics including the synthesis of superheavy nuclei [13][14][15]. The deformations of superheavy nuclei are interesting. Superdeformed prolate [16][17][18] and superdeformed oblate [19] shapes have been predicted. In our previous works [20,21], we discussed the β 6 effects in superheavy nuclei [20] and the β 3 effects on high-K states at the second well of actinide nuclei [21]. In the present paper, using an improved potentialenergy-surface (PES) with the inclusion of reflectionasymmetric β 3 and β 5 deformations, we systematically calculate 248−264

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confidence: 99%

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confidence: 99%

Investigation of octupole effects in superheavy nuclei with improved potential-energy-surface calculations

et al. 2012

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“…But in 150 Ce, all the negative-parity levels are higher than the positive parity ones, and no alternating parity levels between the positive-and negative parity bands are observed. This may indicate that the observed negative parity band (2) in 150 Ce has the octupole vibrational character. Band (3) in 150 Ce built on the 1704.7 keV level is tentatively assigned as a negative parity band.…”

Section: Discussionmentioning

confidence: 92%

“…A nucleus with octupole deformation has an asymmetric shape in its intrinsic frame. Theoretical calculations in the deformed shell model suggested the existence of an octupole deformation island around Z = 56 and N = 88 Ce-Ba nuclear region [1,2]. However, as these nuclei are located in the neutron-rich region, it is difficult to study their high spin states.…”

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Observation of new levels and proposed octupole correlations in neutron-rich150Ce

et al. 2012

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Background : The very neutron-rich 150 Ce is located at the edge of the Z = 56, N=88 octupole deformed island. To study its high spin states and octupole correlations is important for systematically understanding the nuclear structural characteristics in this region. Purpose : To investigate the high spin state levels and to search for octopole correlations in 150 Ce. Methods : The high spin states of 150 Ce are studied by measuring the prompt γ-rays in the spontaneous fission of 252 Cf. The data analysis is by using the γ-γ-γ coincidence methods. The γ → γ(θ) angular correlation measurements are used to determine the spin and indirectly parity of particular levels. Results : A new level scheme of 150 Ce is established. A total of 47 new transitions and 25 new levels are identified comparing with previous results. Six collective bands have been observed and five of them are newly established. An octupole band structure with s = +1 in 150 Ce has been proposed. Systematic analysis for the B(E1)/B(E2) branching ratios, the levels of the octupole bands, the energy differences between negative-and positive-parity bands and the moments of inertia of the bands is carried out in 144,146,148,150 Ce. They give evidences for our assingment of octupole correlations in 150 Ce. The other characteristics of the octupole bands are discussed. Conclusions : An octupole band structure is proposed in 150 Ce. The octupole correlations in 150 Ce are weaker and show more instability than the neighboring lighter Ce isotopes.

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“…There have been intensive interests in the studies of octupole degree of freedom in nuclear structure recently both experimentally [1][2][3][4][5][6][7][8][9] and theoretically [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%