64 research outputs found
Microscopic Structure of High-Spin Vibrational Excitations in Superdeformed 190,192,194Hg
Microscopic RPA calculations based on the cranked shell model are performed
to investigate the quadrupole and octupole correlations for excited
superdeformed bands in 190Hg, 192Hg, and 194Hg. The K=2 octupole vibrations are
predicted to be the lowest excitation modes at zero rotational frequency. At
finite frequency, however, the interplay between rotation and vibrations
produces different effects depending on neutron number: The lowest octupole
phonon is rotationally aligned in 190Hg, is crossed by the aligned
two-quasiparticle bands in 192Hg, and retains the K=2 octupole vibrational
character up to the highest frequency in 194Hg. The gamma vibrations are
predicted to be higher in energy and less collective than the octupole
vibrations. From a comparison with the experimental dynamic moments of inertia,
a new interpretation of the observed excited bands invoking the K=2 octupole
vibrations is proposed, which suggests those octupole vibrations may be
prevalent in SD Hg nuclei.Comment: 22 pages, REVTeX, 12 postscript figures are available on reques
The nuclear collective motion
Current developments in nuclear structure are discussed from a theoretical perspective. First, the progress in theoretical modeling of nuclei is reviewed. This is followed by the discussion of nuclear time scales, nuclear collective modes, and nuclear deformations. Some perspectives on nuclear structure research far from stability are given. Finally, interdisciplinary aspects of the nuclear many-body problem are outlined
Coexistence of collective oblate and superdeformed prolate shapes in 196Pb
The 196Pb nucleus was populated via the 184W(16O,4n)196Pb and 186W(16O,6n)196Pb reactions at beam energies of 98 MeV and 120 MeV, respectively. A new Delta I=1 magnetic dipole band has been observed. This band is believed to be built on a collective oblate configuration involving high-K proton orbitals coupled to two rotationally aligned i13/2 neutrons. The previously observed 196Pb superdeformed band was also populated in these reactions
First observation of collective dipole rotational bands in the neutron-deficient bismuth nuclei
The nucleus 202Bi was populated via the 196Pt(11B,5n)202Bi reaction at a beam energy of 75 MeV. Three regular sequences of magnetic dipole transitions have been found. A comparison is made with the known Delta I=1 rotational bands seen in the neighbouring Pb nuclei. An interpretation in terms of collective oblate configurations involving high-K proton and alignable neutron orbitals is suggested
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