Identifying the spin-trapped character of the isomeric state

J Williams, G Hackman, K Starosta, RS Lubna… - Physical Review C, 2023 - APS
Physical Review C, 2023APS
The properties of a nanosecond isomer in Si 32, disputed in previous studies, depend on the
evolution of proton and neutron shell gaps near the island of inversion. We have placed the
isomer at 5505.2 (2) keV with J π= 5−, decaying primarily via an E 3 transition to the 2 1+
state. The E 3 strength of 0.0841 (10) Wu is unusually small and suggests that this isomer is
dominated by the (ν d 3/2)− 1⊗(ν f 7/2) 1 configuration, which is sensitive to the N= 20 shell
gap. A newly observed 4 1+ state is placed at 5881.4 (13) keV; its energy is enhanced by the …
The properties of a nanosecond isomer in , disputed in previous studies, depend on the evolution of proton and neutron shell gaps near the island of inversion. We have placed the isomer at 5505.2(2) keV with , decaying primarily via an transition to the state. The strength of 0.0841(10) W.u. is unusually small and suggests that this isomer is dominated by the configuration, which is sensitive to the shell gap. A newly observed state is placed at 5881.4(13) keV; its energy is enhanced by the subshell closure. This indicates that the isomer is located in a yrast trap, a feature rarely seen at low mass numbers.
American Physical Society