The level structure of Pm139 has been investigated. The yrast band, based on a decoupled h112 proton orbital, was observed up to J=592-. A sharp backbend with a surprisingly large gain in alignment i=14 was observed at a frequency =0.43 MeV. This large increase in alignment, which is twice that observed in the Pm137 isotope, is due to the simultaneous alignment of both a pair of h112 protons and h112 neutrons. A J=1 sideband based on the neutron-aligned configuration h112(h112)2 with a large negative deformation (-60°) was also observed. The observation of both h112 and h112 alignments is consistent with cranked-shell model calculations.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics