Excited states have been identified in the very neutron-deficient N = Z + 3 nucleus Xe-111 for the first time, using the Ni-58(Ni-58, alpha n) heavy-ion fusion-evaporation reaction. gamma-ray transitions have been unambiguously assigned to Xe-111 by correlation with the characteristic Xe-111 -> Te-107 -> Sn-103 alpha-decay chain using the method of recoil-decay tagging. Inspection of gamma gamma-coincidence data has shown that five of the transitions form a rotational-like sequence. Excitation-energy systematics suggest that the sequence could be the favored signature partner of a band built on an h(11/2) neutron. Aligned angular momenta of states in the band have been compared to analogous bands in neighboring xenon isotopes. The aligned angular momenta for the Xe-111 band are constant over the range of observed rotational frequencies, suggesting that the first pi(h(11/2))(2) alignment is either delayed or absent. It is speculated that the alignment of h(11/2) protons in the presence of neutrons in near-identical h(11/2) orbitals may be affected by neutron-proton interactions or by the onset of octupole correlations.
展开▼
