Evidence For The Occupation of “Hyper-Intruder” Orbitals

High-spin states in 108Cd were studied following the reaction 64Ni(48Ca,4n) at a beam energy of 207 MeV. Gamma rays were detected using the Gammasphere array. Two rotational bands have been observed at very high angular momentum. Measurements of fractional Doppler shifts yielded lower limits for the quadrupole moments and showed that the observed structures are at least as deformed as the superdeformed structures e.g. in the A 150 region, and possibly exceed a 2:1 axis ratio. The existence of very extended shapes has been predicted by cranked Strutinsky calculations, and recent projected shell model calculations suggest that the π i13 2 hyper-intruder orbital is occupied in these newly observed bands.