Particle-core coupling in ³⁷S

Excited states of the neutron-rich N = 21 ³⁷S nucleus have been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of ³⁶S ions with a thin ²⁰⁸Pb target. The magnetic spectrometer, PRISMA, and the γ-ray array, CLARA, were used in the measurements. The level scheme of ³⁷S was established to an excitation energy of 4196 keV and a number of new transitions were observed, in particular that corresponding to the decay of the proposed J^π = (11/2^-) level at an excitation energy of 2776 keV. The structure of the state is discussed within the context of state-of-the-art shell-model calculations using the SDPF-U effective interaction; the main component of the wave function corresponds to the coupling of the odd 1ƒ_7/2 neutron to the first 2⁺ state of the ³⁶S core. The electromagnetic decay properties of the state are discussed within the context of a particle-core coupling model and the shell model. The other members of the multiplet of states are also discussed.