Configuration-constrained potential-energy-surface calculations with reflection asymmetry show enhanced octupole correlations in the $K^{\pi }=6^{-}$ states with configuration $\nu 5/2^{+}\left[633\right]\otimes \nu 7/2^{-}\left[743\right]$ in $N=142,144$ isotones, where a 33.5-$\mu$s isomer has been observed in ${}^{234}$U. High-$K$ isomeric states in other nuclei around ${}^{240}$Pu are calculated to have reflection-symmetric deformations with excitation energies, in agreement with available data.

• Received 21 April 2013

DOI:https://doi.org/10.1103/PhysRevC.87.067304