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Excited states in the nucleus150Tb have been investigated up to spin 39h and 13 MeV excitation energy using the130Te(27Al, 7n) reaction and the EUROGAM array. The theoretical interpretation of the observed states has been performed in the framework of the deformed independent particle model. The analysis of the decay out of the yrast superdeformed band indicates that normal-deformed states with spins between 24h and 28h are fed.

The192Hg nucleus was populated in the160Gd(36S, 4n) reaction at a beam energy of E=159 MeV. Emitted?-rays were detected with the EUROGAM array comprising 43 Compton-suppressed large volume Ge detectors. The level scheme of192Hg has been extended up to an excitation energy of E=10.4 MeV and spin I=34 h. Two new structures, made of competing ?I=1 and ?I=2 transitions have been observed and their connexions with the low-lying levels established. Their lowest levels are located at 6.304 MeV and 6.879 MeV excitation energy. The experimental results are compared with mean-field HF+BCS calculations. It is proposed that the new structures originate from deformation-aligned quasi-proton excitations p(i13/2 * h9/2)K=11 andp (h9/2)K=82, coupled to rotation-aligned quasi-neutron ?(i13/2)n and quasi-proton p(h11/2)2 excitations.

Two rotational bands, with energy spacings characteristic of superdeformed shapes, have been observed following bombardment of150Nd with48Ca. The more intensively populated band consists of 18 transitions and is assigned to194Hg. The depopulation of this band occurs around spin 10. The second band, consisting of at least 16 transitions, was populated less strongly and is tentatively assigned to194Hg also. The lowest level in this band is assigned spin 8. The energy differences between transitions for both bands decrease from ~40 keV at low rotational frequencies to ~30 keV at the highest observed frequencies. The moments of inertia of the bands are similar to those of the two previously observed superdeformed bands in191,192Hg. The similarities and differences of the four known bands in the mercury region are discussed.

Theπh9/2[541 1/2−] band in 167Tm has been studied through the 124Sn(48Ca, p4n)167Tm reaction at Ebeam= 210 MeV. The favoured signature of the πh9/2[541 1/2−] band is observed to spin 61/2h̅. A remarkable small gain in aligned angular momentum at the AB-band crossing has been found. The crossing frequency and the gain in aligned angular momentum for 167Tm are compared with data for the N= 98 isotones of Lu, Ta and Re, and contrasted with Cranked Shell Model predictions, based on frequency diabatic configurations. Large deviations are found for the gain in aligned angular momentum.

New results on the192Hg superdeformed band have been obtained with EUROGAM. The experiment has been performed with the160Gd(36S,4n) reaction at 159 MeV. Above 800 keV the γ-ray energies differ from the previously published ones. Thus the rise of the dynamical moment of inertia above ħω=0.4 MeV is no longer observed. This is in better agreement with recent cranked Hartree-Fock-Bogoliubov calculations.

High spin levels in119Te have been populated following the96Zr (30Si, a 3n)119Te reaction at a beam energy of 135 MeV. The subsequent?-ray deexcitation was studied using?-ray spectroscopic methods. New levels and several spin and parity assignments up toJp=55/2- were established. The decay scheme at high-spin exhibits single-particle characteristics associated with the fully aligned ?(h11/2)3 p(g7/2)2 configuration for the 39/2- level, while the 55/2- level could be interpreted as fully aligned p(d5/2)2? h112/5 g72/-2) configuration.

Two superdeformed (SD) bands have been found in194Tl using the reactions176Yb(23Na,5n) and181Ta(18O,5n). The mass assignments were made from excitation function data. These are the first SD bands found in the mass-190 region that are not in Hg nuclei. The energies of many of the transitions of one of these new SD bands are similar in energy to those in the SD band of192Hg.

A rotational band, with energy spacings characteristic of superdeformed shapes, has been identified in194Pb.The band, which consists of 12 members, was produced in the bombardment of176Yb with24Mg. This band extends the mass-194 region of superdeformation to higher Z.

A superdeformed band, consisting of 12 transitions, is assigned to193Hg on the basis of excitation function and cross bombardment results. A second band is identified which may be the signature partner of this band. In addition, another rotational band is observed which is assigned as the third superdeformed band in194Hg. The similarities of these three bands to those already known in the mercury region are discussed briefly.

The nucleus197Pb was populated via the186W(17O,6n)197Pb reaction at beam energies of 98 and 110 MeV. Two regular ?I=1 bands of magnetic dipole transitions have been found. Possible interpretations in terms of collective oblate configurations involving high-K proton orbitals coupled to three i13/2neutrons are discussed. The similarities between several of the bands discovered in197–200pbnuclei are emphasized.