| 1. |
- Smith, J. F., et al.
(author)
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Identification of excited states in 119Ba
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:4
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Journal article (peer-reviewed)abstract
- Excited states have been identified in the very neutron-deficient 119Ba nucleus. Two bands have been observed, which are likely to be based on h11/2 and (g7/2d5/2) neutron orbitals. Despite this being the first observation of excited states in 119Ba, the bands extend to (75/2)ℏ and (79/2)ℏ, respectively. The bands have been assigned to 119Ba using gamma-recoil and gamma-x-ray coincidences. Several quasiparticle alignments have been identified, involving neutron (h11/2)2 and proton (h11/2)2 aligned configurations. Furthermore, the bands show features which are reasonably consistent with smooth band termination at high spin. Theoretical results for 119Ba are discussed within the framework of cranked Woods-Saxon and Nilsson-Strutinsky calculations.
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| 2. |
- Cardona, R., et al.
(author)
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High-spin structure of normal-deformed bands in 84Zr
- 2003
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 68, s. 1-024303
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Journal article (peer-reviewed)abstract
- The reaction 58Ni(32S, α2p) at E lab= 135 MeV was used to populate high-spin states in 84Zr. The complete GAMMASPHERE and MICROBALL arrays were used to obtain clean γ- γ- γ line shapes to be analyzed by the Doppler shift attenuation method and to determine 27 lifetimes in the ground-state band and in two excited bands. Side-feeding times were also measured by comparing the line shapes gated with transitions above and below the state under study. The deduced electric quadrupole moments for the ground-state band are consistent with a very slow reduction with frequency with values ranging between 2.4(3) and 2.0(1)e b. The negative-parity bands feature also an approximate constancy of quadrupole moment with values similar to those in the ground-state band. Cranking calculations agree with this behavior in both parity bands and suggest an interpretation of the upper states in the ground-state band as part of a very slowly terminating band. Shell-dependent cranked Nilsson calculations explain a fourth γ cascade as pertaining to a noncollective structure terminating at I = 20+.
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| 3. |
- Döring, J., et al.
(author)
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Band terminations in the valence space of 86Zr
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:3, s. 343101-343106
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Journal article (peer-reviewed)abstract
- High-spin states in 86Zr up to 30+ and 27- were observed via the 58Ni(32S,4p) reaction at 135 MeV beam energy using the combined GAMMASPHERE and MICROBALL systems. Calculations performed with the configuration-dependent shell-correction approach show that these states are built from six g9/2 neutrons and at most four protons excited from the p1/2,p3/2,f5/2 subshells to the g9/2 subshell at small deformation. The highest observed states at 27- and 30+ are interpreted as band-terminating states with the latter having the highest spin available in the valence space for 86Zr.
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| 4. |
- LaFosse, D. R., et al.
(author)
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Collective structures and band termination in 107Sb
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:1
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Journal article (peer-reviewed)abstract
- High-spin states in the near proton-dripline nucleus 107Sb have been identified, and collectivity in this nucleus has been observed for the first time in the form of two rotational bands. One of the observed rotational structures is a ΔI = 1 band, and is interpreted as based on a π(g9/2)-1 ⊗ π(g7/2d5/2)2 proton configuration. A second structure has ΔI = 2 character, and is explained as being based on a πh11/2⊗[π(g9/2)-2 ⊗ π(g7/2d5/2)2] proton configuration through comparison with cranked Nilsson-Strutinsky model calculations. The calculations predict that this band terminates at a spin of 79/2 (Latin small letter h with stroke).
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| 5. |
- Ma, W. C., et al.
(author)
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Competition between terminating and collective structures above spin 40ℏ in 154Dy
- 2002
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 65, s. 1-034312
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Journal article (peer-reviewed)abstract
- High-spin states in 154Dy were studied with the Gammasphere spectrometer using the 36S(122Sn,4n) reaction. Band terminating states were identified in the spin range I= (36-48)ℏ, and were found to compete with collective rotational cascades up to the highest observed spins. Several "sidebands" feeding the terminating structures were identified as well. A band dominated by M1 transitions was observed to terminate at Iπ = 42-. The data are interpreted within the framework of configuration-dependent cranked Nilsson-Strutinsky calculations without pairing.
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| 6. |
- Pfohl, J., et al.
(author)
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Highly deformed rotational structures in 136Pm
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:3, s. 313041-313045
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Journal article (peer-reviewed)abstract
- Four highly deformed structures in the odd-odd nucleus 13661Pm75 were observed via the 105Pd(35Cl,2p2n) reaction at 180 and 173 MeV using the GAMMASPHERE γ-ray spectrometer and the Microball charged-particle detector array. Quadrupole moment measurements were performed on all of the bands. In contrast to lighter odd-Ζ Pm and Pr nuclei, bands based on the g9/2[404]9/2 proton orbital were not observed. Instead, the four observed sequences are assigned as a coupling of an i13/2 neutron with the low-Ω h11/2 and mixed d5/2g7/2 orbitals. Comparisons with neighboring highly deformed structures are discussed and cranked Nilsson-Strutinsky calculations for 136Pm are presented.
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| 7. |
- Starosta, K., et al.
(author)
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Smooth band termination at high spin in 113I
- 2001
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 64:1, s. 143041-1430419
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Journal article (peer-reviewed)abstract
- The 113I nucleus has been studied using the 58Ni(58Ni,3p) reaction at 250 MeV with the Gammasphere/ Microball facility. Gamma-ray three-and four-fold data gated by charged particle combinations were analyzed. Multipolarities of the γ rays were assigned following the angular correlation measurements. The present study is focused on the high spin properties, where the structure is dominated by 2p-2h excitations across the Z=50 gap. Ten decoupled bands showing the features of smooth band termination were observed; three of those bands are linked to known low-spin states, which allows the identification of configurations by direct comparisons with configuration-dependent cranked Nilsson-Strutinsky calculations. The yrast band, which was linked along with the signature partner, was followed up to (101/2+) and ℏω∼1.3 MeV. The other linked band was a negative-parity band observed up to (95/2-). Tentative configurations for the unlinked bands are discussed. Comparisons with the theoretical results suggest that the band built on a configuration involving the neutron i13/2 intruder orbital originating from the N=6 harmonic oscillator subshell was observed in this experiment.
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| 8. |
- Svensson, C. E., et al.
(author)
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Collective rotational motion in the N=Z nucleus 36Ar
- 2001
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In: Nuclear Physics A. - 0375-9474. ; 682:1-4, s. 1-11
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Journal article (peer-reviewed)abstract
- A superdeformed rotational band has been identified in the N = Z nucleus 36Ar, firmly linked to known low-spin states, and observed to its high-spin termination at Iπ = 16+. Lifetime measurements by the Doppler shift attenuation method establish a large low-spin deformation (β2 ≈ 0.46) and a decrease in the collectivity as the band approaches termination. Comparisons with cranked Nilsson-Strutinsky and large-scale spherical shell model calculations lead to a consistent description of the band based on a configuration in which four particles are promoted to the pf shell. With two major shells active for both protons and neutrons, yet a valence space dimension small enough to be approached from the shell model perspective, this band offers an excellent opportunity to investigate the microscopic structure of collective rotational motion in nuclei.
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| 9. |
- Svensson, C. E., et al.
(author)
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Lifetimes of superdeformed rotational states in 36Ar
- 2001
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 63:6, s. 613011-613015
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Journal article (peer-reviewed)abstract
- Lifetimes have been measured in a superdeformed rotational band recently identified in the N = Z nucleus 36Ar. A large low-spin quadrupole deformation (β2=0.46±0.03) is confirmed and a decrease in the collectivity is observed as the high-spin band termination at Iπ=16+ is approached. Detailed comparisons of the experimental B(E2) values with the results of cranked Nilsson-Strutinsky and large-scale (s1/2d3/2)-pf spherical shell model calculations indicate the need for a more refined treatment of transition matrix elements close to termination in the former, and the inclusion of the complete sd-pf model space in the latter description of this highly-collective rotational band.
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| 10. |
- Svensson, C. E., et al.
(author)
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Lifetimes of superdeformed rotational states in [Formula Presented]
- 2001
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 63:6, s. 5-5
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Journal article (peer-reviewed)abstract
- Lifetimes have been measured in a superdeformed rotational band recently identified in the [Formula Presented] nucleus [Formula Presented] A large low-spin quadrupole deformation [Formula Presented] is confirmed and a decrease in the collectivity is observed as the high-spin band termination at [Formula Presented] is approached. Detailed comparisons of the experimental [Formula Presented] values with the results of cranked Nilsson-Strutinsky and large-scale [Formula Presented] spherical shell model calculations indicate the need for a more refined treatment of transition matrix elements close to termination in the former, and the inclusion of the complete [Formula Presented] model space in the latter description of this highly-collective rotational band.
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