Spin alignment in superdeformed Hg nuclei

One of the superdeformed rotational bands in ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$ has transition energies (rotational frequencies) that are equal within about 0.1% to those of the (only known) band in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Hg}$. This excited (two-quasiparticle) band in ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$ has an aligned spin of (1.00±0.04)ħ relative to the very similar band in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Hg}$, suggesting an interpretation in terms of aligned pseudo (intrinsic) spin. The implied pseudospin symmetry may be a clue as to why the rotational frequencies are so similar.