A. O. Evans, E. S. Paul, J.
Simpson, M. A. Riley et al.,
Physical Review Letters 92 (2004)
252502
The
angular-momentum induced transition from a deformed state of collective
rotation to a non-collective configuration has been studied. In 157Er
this transition manifests itself as favored band termination near I=45 ħ. The feeding of these band
terminating
states has been investigated for the first time using the Gammasphere
spectrometer. Many weakly populated states lying at high excitation energy that
decay into these special states have been discovered. Cranked Nilsson-Strutinsky
calculations suggest that these states arise from weakly collective
``core-breaking''
configurations.