Rotational bands with identical transition energies in actinide nuclei

We point out the existence of ground-state rotational bands with identical transition energies (up to spin 8ħ) in ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{244}{}_{}{}^{}\mathrm{Cm}$, ${}_{}{}^{246}{}_{}{}^{}\mathrm{Cm}$, and ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cf}$. The corresponding transitions in the ground-state bands of ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ have identical energies (within ∼2 keV) up to spin 24ħ. These features are very similar to those recently observed for superdeformed bands in the mass-150 and mass-190 regions and suggest that the phenomenon of identical bands is not restricted to superdeformed bands.