New results on super deformed bands in Hg and Tl nuclei

New results have been obtained on superdeformed states in ¹⁹⁰Hg, ¹⁹¹T1 and ¹⁹²T1. For ¹⁹⁰Hg, the previously identified superdeformed band has been extended up to a rotational frequency of h {combining short solidus overlay}ω ≥ 0.40 MeV by combining data from several different experiments. The extracted dynamical moment of inertia T⁽²⁾ vs h{stroke}ω exhibits a distinct change in slope at h {combining short solidus overlay}ω = 0.32 MeV. For ¹⁹¹T1 and ¹⁹²T1, two and six superdeformed bands have been identified in these nuclei, respectively. Six of these eight bands exhibit a smooth rise in T⁽²⁾ with h{stroke}ω characteristic of the other superdeformed bands identified in this mass region while the remaining two bands which are in ¹⁹²T1 show a constant T⁽²⁾with h{stroke}ω. This new result can be understood in terms of Pauli blocking of quasiparticle alignments in high-N intruder orbitale. 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 T⁽²⁾ seen in the other superdeformed bands of this mass region.