Structure of Yrast Traps

Abstract

An "island" of isomeric states with high multiplicities found in a recent experiment are interpreted as "yrast traps" in deformed nuclei rotating around a symmetry axis. According to our interpretation, a group of trap states for neutron numbers around 82 and angular momenta below 40 is connected with the nuclear shell structure for weakly deformed potentials. A second group of traps situated in a more narrow region around neutron number 82 and with angular momentum around 50 is attributed to the occurence of shell structure for a ratio of axes 2: 3.