A ${}^{160}\mathrm{Gd}$ beam was accelerated to an energy of 1000 MeV and, separately, bombarded thick targets of ${}^{154}\mathrm{Sm}$ and ${}^{164}\mathrm{Dy}$ in order to observe neutron-rich, rare-earth nuclei via deep-inelastic collision processes. Gammasphere was utilized to observe $\gamma$-ray emissions. Many new states and transitions were observed in ${}^{160}\mathrm{Gd}$ as a result of so-called unsafe Coulomb excitation. The ground-state band in ${}^{160}\mathrm{Gd}$ has been extended to $I^{\pi }={20}^{+}$ and a rotational band based on the $K^{\pi }=4^{+}$ state, previously associated with a hexadecapole vibration, was observed up to ${18}^{+}$. The quasiparticle configuration of the $K^{\pi }=4^{+}$ band has been determined, and its unusual alignment behavior may result from a possible quenching of static neutron pairing. In addition, the band based on the [523]5/2 quasineutron orbital in ${}^{161}\mathrm{Gd}$ was extended from $11/2^{-}$ to $33/2^{-}$ and also displays the same unusual alignment behavior.

• Received 22 October 2020
• Revised 14 January 2021
• Accepted 11 March 2021

DOI:https://doi.org/10.1103/PhysRevC.103.034322