Exotic Collective Excitations at High Spin: Triaxial Rotation and Octupole Condensation

Doctoral Dissertation
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Abstract

In this thesis work, two topics, triaxiality and reflection asymmetry, have been discussed. Band structures in 163Tm were studied in a “thin” target experiment as well as in a DSAM lifetime measurement. Two new excited bands were shown to be characterized by a deformation larger than that of the yrast sequence. These structures have been interpreted as Triaxial Strongly Deformed bands associated with particle-hole excitations, rather than with wobbling. Moreover, the Tilted-Axis Cranking calculations provide a natural explanation for the presence of wobbling bands in the Lu isotopes and their absence in the neighboring Tm, Hf and Ta nuclei. A series of so-called “unsafe” Coulomb excitation experiments as well as one-neutron transfer measurements was carried out to investigate the role of octupole correlations in the 238,240,242Pu isotopes. Some striking differences exist between the level scheme and deexcitation patterns seen in 240Pu, and to a lesser extent in 238Pu, and those observed in 242Pu and in many other actinide nuclei such as 232Th and 238U, for example. The differences can be linked to the strength of octupole correlations, which are strongest in 240Pu. Further, all the data find a natural explanation within the recently proposed theoretical framework of octupole condensation.

Attributes

Attribute NameValues
URN
  • etd-12132007-005645

Author Xiaofeng Wang
Advisor Prof. Stefan G. Frauendorf
Contributor Prof. Philippe Collon, Committee Member
Contributor Prof. Robert V. F. Janssens, Committee Co-Chair
Contributor Prof. Gordon Berry, Committee Member
Contributor Prof. Stefan G. Frauendorf, Committee Member
Contributor Prof. Umesh Garg, Committee Co-Chair
Degree Level Doctoral Dissertation
Degree Discipline Physics
Degree Name PhD
Defense Date
  • 2007-12-07

Submission Date 2007-12-13
Country
  • United States of America

Subject
  • Gamma ray

  • High spin

  • Octupole

  • Triaxial

  • Nuclear structure

Publisher
  • University of Notre Dame

Language
  • English

Record Visibility and Access Public
Content License
  • All rights reserved

Departments and Units

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