Two low-lying neutron-unbound excited states of 24 O, populated by proton-knockout reactions on 26 F, have been measured using the MoNA and LISA arrays in combination with the Sweeper Magnet at the Coupled Cyclotron Facility at the NSCL using invariant mass spectroscopy. The current measurement confirms for the first time the separate identity of two states with decay energies 0.51(5) MeV and 1.20(7) MeV, and provides support for theoretical model calculations, which predict a 2 + first excited state and a 1 + higher energy state. The measured excitation energies for these states, 4.70(15) MeV for the 2 + level and 5.39(16) MeV for the (1 + ) level, are consistent with previous lower-resolution measurements, and are compared with five recent model predictions.

The high-spin decay of 71 Se was studied using the 54 Fe( 23 Na,αpn) reaction at 80 MeV and the Florida State University Compton-suppressed Ge array consisting of three clover detectors and seven single-crystal detectors. Based on prompt γ -γ coincidences measured in the experiment, the known level scheme was enhanced and extended to higher spin with 19 new transitions. A band that was previously suggested to have positive parity was reassigned as the "missing" signature partner of an existing negative-parity band. Spins were assigned based on directional correlation of oriented nuclei ratios. Lifetimes of 17 excited states were measured using the Doppler-shift attenuation method. Experimental Q t values imply an intermediate degree of collective behavior for 71 Se at high spin. Theoretical Q t values determined from cranked Woods-Saxon (CWS) calculations show better agreement with the experimental ones for the positive-parity states than the negative-parity states. Shape competition and γ softness characterize the low-spin states of the lowest positive-and negative-parity bands based on the CWS calculations. At high spin, triaxial shapes with γ > 0 • are predicted.