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Title: High-spin states and collective oblate bands in the odd-odd {sup 138}Pr nucleus

Abstract

High-spin states in the odd-odd {sup 138}Pr nucleus were reinvestigated with the reaction {sup 128}Te({sup 14}N,4n) at a beam energy of 64 MeV. Six collective bands were observed, and two of them were newly identified. For the {pi}h{sub 11/2}x{nu}h{sub 11/2} band, high-spin states are followed up to I{sup {pi}}=16{sup +}. The spin values for this band have been reassigned based on the systematical comparison with the neighboring nuclei. The observed band crossing is proposed to be due to the alignment of protons, and the signature inversion with the neutron number changing in La and Pr isotopes has been discussed. The other five collective bands are proposed to be based on oblate deformation with {gamma}{approx}-60 deg.

Authors:
; ; ; ; ;  [1]; ; ; ; ; ;  [2]
  1. Department of Physics, Tsinghua University, Beijing 100084 (China)
  2. China Institute of Atomic Energy, Beijing, 102413 (China)
Publication Date:
OSTI Identifier:
20995117
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034304; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COMPARATIVE EVALUATIONS; HEAVY ION REACTIONS; HIGH SPIN STATES; MASS NUMBER; MEV RANGE 10-100; NEUTRONS; NITROGEN 14; PRASEODYMIUM 138; PROTONS; SPIN; TELLURIUM 128

Citation Formats

Li, M. L., Zhu, S. J., Che, X. L., Yu, Y. N., Chen, Y. J., Ding, H. B., Zhu, L. H., Wu, X. G., Wen, S. X., He, C. Y., Cui, X. Z., and Liu, Y.. High-spin states and collective oblate bands in the odd-odd {sup 138}Pr nucleus. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034304.
Li, M. L., Zhu, S. J., Che, X. L., Yu, Y. N., Chen, Y. J., Ding, H. B., Zhu, L. H., Wu, X. G., Wen, S. X., He, C. Y., Cui, X. Z., & Liu, Y.. High-spin states and collective oblate bands in the odd-odd {sup 138}Pr nucleus. United States. doi:10.1103/PHYSREVC.75.034304.
Li, M. L., Zhu, S. J., Che, X. L., Yu, Y. N., Chen, Y. J., Ding, H. B., Zhu, L. H., Wu, X. G., Wen, S. X., He, C. Y., Cui, X. Z., and Liu, Y.. Thu . "High-spin states and collective oblate bands in the odd-odd {sup 138}Pr nucleus". United States. doi:10.1103/PHYSREVC.75.034304.
@article{osti_20995117,
title = {High-spin states and collective oblate bands in the odd-odd {sup 138}Pr nucleus},
author = {Li, M. L. and Zhu, S. J. and Che, X. L. and Yu, Y. N. and Chen, Y. J. and Ding, H. B. and Zhu, L. H. and Wu, X. G. and Wen, S. X. and He, C. Y. and Cui, X. Z. and Liu, Y.},
abstractNote = {High-spin states in the odd-odd {sup 138}Pr nucleus were reinvestigated with the reaction {sup 128}Te({sup 14}N,4n) at a beam energy of 64 MeV. Six collective bands were observed, and two of them were newly identified. For the {pi}h{sub 11/2}x{nu}h{sub 11/2} band, high-spin states are followed up to I{sup {pi}}=16{sup +}. The spin values for this band have been reassigned based on the systematical comparison with the neighboring nuclei. The observed band crossing is proposed to be due to the alignment of protons, and the signature inversion with the neutron number changing in La and Pr isotopes has been discussed. The other five collective bands are proposed to be based on oblate deformation with {gamma}{approx}-60 deg.},
doi = {10.1103/PHYSREVC.75.034304},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • High spin states in {sup 139}Nd nucleus have been reinvestigated with the reaction {sup 128}Te ({sup 16}O, 5n) at a beam energy of 90 MeV. The level scheme has been expanded with spin up to 47/2({Dirac_h}/2{pi}). At low spin, the yrast collective structure built on the {nu}h{sub 11/2}{sup -1} multiplet shows a triaxial shape with {gamma}{approx_equal}32 deg. according to calculations of the triaxial rotor-plus-particle model. The configurations for some high spin states have been discussed from a systematic comparison with neighboring nuclei. Three collective oblate bands with {gamma}{approx}-60 deg. at high spin were identified for the first time. A bandmore » crossing is observed around ({Dirac_h}/2{pi}){omega}{approx}0.4 MeV in one oblate band based on the 25/2{sup -} level. The characteristics for these oblate bands have been discussed.« less
  • Cited by 2
  • The level structure of the transitional even-even {sup 136}Ce nucleus has been investigated using the {sup 122}Sn({sup 18}O, 4{ital n}{gamma}) reaction. The prominent structure observed at high spin is a {Delta}{ital I}=1 rotational band, populated with {similar to}25% intensity of the 2{sup +}{r arrow}0{sup +} transition, which has a low dynamic moment of inertia {lt}20{h bar}{sup 2} MeV{sup {minus}1} for frequencies below {h bar}{omega}=0.45 MeV. This band is interpreted in terms of a two-quasiproton-two-quasineutron configuration with a shape close to the collectively rotating {gamma}={minus}60{degree} oblate shape, and is related to the oblate {pi}{ital h}{sub 11/2}{direct product}({nu}{ital h}{sub 11/2}){sup 2} configurationmore » seen in several nearby odd-{ital Z} nuclei. The systematics of such oblate rotational bands in this mass region are discussed. Other {Delta}{ital I}=2 bands, built on states including {ital h}{sub 11/2} quasineutron orbitals, are also associated with collective oblate rotation. In addition, tentative evidence is presented for a weak band ({lt}2% intensity), showing an enhanced dynamic moment of inertia {similar to}57{h bar}{sup 2} MeV{sup {minus}1}, built on the highly deformed ({nu}{ital i}{sub 13/2}){sup 2} prolate configuration.« less
  • An in-beam [gamma]-ray study performed with the [sup 121]Sb([sup 19]F,4[ital n]) reaction has established the high spin level structure of the [ital N]=78 nucleus [sup 138]Nd. States up to [ital I]=21[h bar] and 8.5 MeV excitation energy have been indentified. High spin states are described in the framework of the cranking model and of the interacting boson model with broken pairs. The calculations reproduce levels up to [ital I]=18[h bar] including the two 10[sup +] states which, from the feeding cascades, are identified as the [nu][ital h][sub 11/2][sup [minus]1] and [pi][ital h][sub 11/2][sup 2] excitations. Cranked Strutinsky type calculations predictmore » opposite shapes for the two different types of excitations.« less
  • The odd-proton nucleus /sup 133/Pr has been investigated using the /sup 118/Sn(/sup 19/F,4n) and /sup 117/Sn(/sup 19/F,3n) reactions. Several rotational bands could be followed up to high spins. The yrast band, built on a decoupled h/sub 11/2 proton, shows an upbend at (h2..pi..)..omega.. = 0.43 MeV when two additional h/sub 11/2 protons align. Two positive-parity side bands of opposite signature were established, both showing a band crossing at (h2..pi..)..omega.. = 0.27 MeV with a gain in alignment ..delta..i/sub x/)similarreverse arrowto)8(h2..pi..) when two h/sub 11/2 protons align. This low crossing frequency, compared to that observed in the /sup 132/Ce core nucleus,more » is partly explained by a reduction in the proton pairing gap. Three ..delta..I = 1 bands were observed;the lowest one is believed to represent a collective rotation of an oblate shape. The shape change is induced by the alignment of a pair of h/sub 11/2 neutrons from the upper midshell driving the nucleus from a prolate to an oblate shape« less