New results on superdeformed bands in Hg and Tl nuclei

New results have been obtained on superdeformed states in 190Hg, 191Tl, and 192Tl. For 190Hg, the previously identified superdeformed band has been extended up to a rotational frequency of ℎω ≥ 0.40 MeV by combining data from several different experiments. The extracted dynamical moment of inertia J(2) vs ℎω exhibits a distinct change in slope at ℎω = 0.32 MeV. For 191Tl and 192Tl, two and six superdeformed bands have been identified in these nuclei, respectively. Six of these eight bands exhibit a smooth rise in J(2) with ℎω characteristic of the other superdeformed bands identified in this mass region while the remaining two bands which are in 192Tl show a constant J(2) with ℎω. This new result can be understood in terms of Pauli blocking of quasiparticle alignments in high-N intruder orbitals. The new result for 190Hg is interpreted as evidence of a band interaction at the highest frequencies due to the rotational alignment of a pair of quasiparticles into these same intruder orbitals. These two new features taken together represent the first conclusive evidence that the alignment of intruders is responsible for the smooth rise in J(2) seen in the other superdeformed bands of this mass region