Intruder negative-parity states of neutron-rich Si-33

Yrast states in the neutron-rich (33)(14)Si(19) nucleus have been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of (36)S ions with a thin (208)Pb target. An experimental setup that combines the large-acceptance magnetic spectrometer PRISMA and the high-efficiency gamma-ray detection array CLARA was used in the experiment. Four new gamma-ray photopeaks at energies of 971, 1724, 1772, and 2655 keV were observed and assigned to the (33)Si level scheme. The experimental level scheme is compared with the results of 1h omega p-sd-pf large-scale shell-model calculations using the recently developed PSDPFB effective interaction; good agreement is obtained. The structure of the populated states of (33)Si is discussed within the context of an odd neutron coupled to states of the (32)Si core.