Configuration and bandhead spin assignments for the 2-quasiparticle rotational bands in the neutron-rich nuclei ${}^{154,156}$Pm

Abstract

The rotational bands in the neutron-rich nuclei ${}^{153-157}$Pm are investigated by a particle-number conserving method. The kinematic moments of inertia for the 1-quasiparticle bands in odd-$A$ Pm isotopes ${}^{153,155,157}$Pm are reproduced quite well by the present calculation. By comparison between the experimental and calculated moments of inertia for the three 2-quasiparticle bands in the odd-odd nuclei ${}^{154,156}$Pm, their configurations and bandhead spins have been assigned properly. For the 2-quasiparticle band in ${}^{154}$Pm, the configuration is assigned as $\pi 5/2^{-}[532]\otimes \nu 3/2^{-}[521]$ ($K^{\pi }=4^{+}$) with the bandhead spin $I_0=4\hslash$. In ${}^{156}$Pm, the same configuration and bandhead spin assignments have been made for the 2-quasiparticle band with lower excitation energy. The configuration $\pi 5/2^{+}[413]\otimes \nu 5/2^{+}[642]$ ($K^{\pi }=5^{+}$) with the bandhead spin $I_0=5\hslash$ is assigned for that with higher excitation energy.

Comments: 6 figures, 2 tables