Abstract
Excited states in the nucleus have been investigated by in-beam γ-ray spectroscopic techniques using the Gammasphere array. The reaction at a beam energy of 134.5 MeV was used to populate states of The level scheme of has been extended up to 5.1 MeV excitation energy and spin The lower part (below ) presents the general features common in all odd-mass Pb isotopes, i.e., spherical states built on the isomer, with bandlike structures that follow weak-coupling expectations. In the upper part of the level scheme two dipole bands are observed with bandhead energies of and 2.291 MeV. A comparison of dipole band 1 with the strongest negative-parity dipole bands in the heavier odd-mass Pb isotopes reveals striking similarities. The spherical states are interpreted as the coupling of the neutron hole to the yrast states in the even-mass core. The dipole bands are interpreted as cascades which arise from the coupling of two protons in high- orbitals above the gap to neutron holes in the orbital.
- Received 10 November 1997
DOI:https://doi.org/10.1103/PhysRevC.57.1624
©1998 American Physical Society