Excited states in ${}^{126}\mathrm{Ce}$ have been observed with the GAMMASPHERE γ-ray detector array, used in conjunction with the MICROBALL charged-particle detector. The reaction ${}^{64}\mathrm{Zn}{(}^{64}\mathrm{Zn},\mathrm{xpn}\alpha )$ (beam energy 260 MeV) was used to populate a wide range of nuclei in the neutron-deficient region with $A\approx 120.$ ${}^{126}\mathrm{Ce}$ was populated via the $2p$ evaporation channel. The three previously observed bands have been extended to higher spins and some other structures have been identified. The yrast band shows evidence of a delayed neutron alignment occurring at a rotational frequency ω≈0.5 MeV/ħ as observed in the neighboring odd-A nucleus ${}^{127}\mathrm{Pr}.$ One of the two excited bands shows evidence for a similar crossing at a slightly lower frequency and also exhibits a sudden gain in alignment at ω=0.57 MeV/ħ. The third band may involve the coupling of a γ-vibrational state. All three rotational bands are discussed in terms of standard and extended cranked shell model calculations.

• Received 31 May 2000

DOI:https://doi.org/10.1103/PhysRevC.63.054307