Lifetimes of yrast states in 180 Hg up to the 8 + state and of the 9 − state have been extracted from recoil-decay tagged γ -ray spectra by using the recoil distance Doppler-shift method. In addition, lifetimes of yrast states up to the 10 + state in 182 Hg have been extracted from recoil-gated γ γ -coincidence spectra. The present study addresses the evolution of collectivity of two competing shapes in neutron-deficient Hg nuclei as a function of A and the configuration mixing at low spin.

The 7 H and 6 H nuclear systems were investigated via transfer reactions with a 8 He beam at 15.4A MeV impinging in a 12 C target. The experimental setup allowed a complete reconstruction of the reaction kinematics with the MAYA gas detector, based on the active-target concept, where the carbon atoms of the filling isobutane played also the role of reaction target. The 7 H resonance was observed at 0.57 +0.42 −0.21 MeV above the 3 H + 4n threshold with a width of 0.09 +0.94 −0.06 MeV. The 6 H system was formed at 2.91 +0.85 −0.95 MeV with a resonance width of 1.52 +1.77 −0.35 MeV. These results show the availability of nuclear structure information well outside the bounding limits, resulting in an extraordinary input to improve the present models and understanding of nuclear matter.

Lifetimes of excited states in 182 Hg were extracted from recoil-gated γ -ray spectra and recoil-gated γ γ -coincidence matrices using the recoil distance Doppler-shift method. States were populated using the 96 Mo( 88 Sr,2n) 182 Hg fusion-evaporation reaction. Measured lifetimes allowed transition probabilities, transition quadrupole moments, quadrupole deformation parameters, and transition dipole moments to be deduced for the band formed by the odd-spin yrast states. The experimental results confirm the low degree of octupole collectivity in this mass region.

The α decay of 159 Re has been observed for the first time in reactions of 300 MeV 58 Ni ions with an isotopically enriched 106 Cd target. The 159 Re ions were separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The α decay emanates from the proton-emitting πh 11/2 state in 159 Re with an energy of E α = 6776 ± 26 keV and a branching ratio of 7.5 ± 3.5%. This α decay populates a state in the closed neutron shell nucleus 155 Ta, which decays by emitting 1444 ± 15 keV protons with a half-life of 2.9 +1.5 −1.1 ms. These values are consistent with the emission of the proton from a πh 11/2 orbital. These results fit in with the systematics of proton and α-particle separation energies in the region, but disagree with the previously reported decay properties of 155 Ta.

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