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Type of Document Dissertation Author Zhu, Shaofei Author's Email Address szhu@nd.edu URN etd-03012004-010703 Title Exotic Rotation in Weakly Deformed and Triaxial Nuclei Degree Doctor of Philosophy Department Physics Advisory Committee
Advisor Name Title Dennis Jacobs Committee Chair Ani Aprahamian Committee Member Michael Douglas Hildreth Committee Member Stefan G Frauendorf Committee Member Umesh Garg Committee Member Keywords
- chiral symmetry
- antimagnetic rotation
- gamma spectroscopy
- nuclear deformation
Date of Defense 2003-12-11 Availability mixed Abstract Antimagnetic rotation in weakly deformed nuclei Pd100,101, and chiral rotation in triaxial nuclei Nd135,136 have been investigated by means of gamma-ray spectroscopic measurements. These two modes of rotation are quite different from "standard" rotational motion observed in well deformed nuclei. In these new modes, the total angular momentum either originates purely from a few particles in high-j orbitals, or these orbitals couple to collective motion of a triaxial core. Two cascades of four "rotational-band-like' transitions were observed in Pd100 and Pd101, respectively, and have been proposed as corresponding to antimagnetic rotation,based on the observed spectroscopic properties and a comparison with calculations in the configuration-dependent cranking Nilsson-Strutinsky formalism. Two Delta(I)=1 bands
with close excitation energies and the same parity were observed in Nd135. These bands are directly linked by Delta(I)=1 and Delta(I)=2 transitions. The chiral nature of these two bands is confirmed by comparison with three-dimensional tilted axis cranking calculations. This is the first observation of a three-quasiparticle chiral structure and establishes the primarily geometric nature of this phenomenon. Although there are no chiral partner
bands observed in even-even nucleus Nd135 from our data, TAC calculations indeed give chiral solutions related to several Delta(I)=1 bands
in the nucleus Nd136.
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