High-spin spectroscopy and quasiparticle alignments in ^124,125Ce

Rotational bands have been studied to high spins in the neutron-deficient ^124,125Ce nuclei. The nuclei were populated using the ⁶⁴Zn(⁶⁴Zn,2p2n)¹²⁴Ce and ⁶⁴Zn(⁶⁴Zn,2pn)¹²⁵Ce reactions, with a beam energy of 260 MeV. High-fold γ-ray coincidence data were collected using the Gammasphere germanium-detector array. The Microball charged-particle detector array was used to provide channel selection. The previously established level structures of both ^124,125Ce have been extended to high spins (∼30ℏ). In addition, several new bands have been identified. The alignments of pairs of h_11∕2 neutrons and protons are observed in both nuclei. The alignments are compared to the predictions of Woods-Saxon cranked shell model calculations and to the systematics of h_11∕2 quasiparticle alignments in neighboring nuclei. The apparent ability of the cranked shell model to explain the h_11∕2 neutron alignments in ^124,125Ce highlights the previously reported discrepancies between experiment and theory for the ¹²⁸Ce isotope and, to a lesser extent, ¹²⁶Ce.