The Coulomb excitation experiment to study electromagnetic properties of the heaviest stable Mo isotope, 100 Mo, was performed using a 76 MeV 32 S beam from the Warsaw cyclotron U-200P. Magnitudes and relative signs of 26 E1, E2, E3, and M1 matrix elements coupling nine low-lying states in 100 Mo were determined using the least-squares code GOSIA. Diagonal matrix elements (related to the spectroscopic quadrupole moments) of the 2 + 1 , 2 + 2 , and 2 + 3 states as well as the 4 + 1 state were extracted. The resulting set of reduced E2 matrix elements was complete and precise enough to obtain, using the quadrupole sum rules approach, quadrupole deformation parameters of 100 Mo in its two lowest 0 + states: ground and excited. The overall deformation of the 0 + 1 and 0 + 2 states in 100 Mo is of similar magnitude, in both cases larger compared to what was found for the neighboring isotopes 96 Mo and 98 Mo. At the same time, the asymetry parameters obtained for both states strongly differ, indicating a triaxial shape of the 100 Mo nucleus in the ground state and a prolate shape in the excited 0 + state. Low-energy quadrupole excitations of the 100 Mo nucleus were studied in the frame of the general quadrupole collective Bohr Hamiltonian model (GBH). The potential energy and inertial functions were calculated using the adiabatic time-dependent Hartree-Fock-Bogoliubov (ATDHFB) method starting from two possible variants of the Skyrme effective interaction: SIII and Sly4. The overall quadrupole deformation parameters resulting from the GBH calculations with the SLy4 variant of the Skyrme interaction are slightly closer to the experimentally obtained values than those obtained using SIII.

Article:Bree, N., Wrzosek-Lipska, K., Petts, A. et al. (67 more authors) (2014) Shape coexistence in the neutron-deficient even-even 182-188Hg isotopes studied via Coulomb excitation.

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The neutron-deficient mercury isotopes, 184,186 Hg, were studied with the Recoil Distance Doppler-Shift (RDDS) method using the Gammasphere array and the Köln Plunger device. The Differential Decay Curve Method (DDCM) was employed to determine the lifetimes of the yrast states in 184,186 Hg. An improvement on previously measured values of yrast states up to 8 + is presented as well as first values for the 93 state in 184 Hg and 10 + state in 186 Hg. B(E2) values are calculated and compared to a two-state mixing model which utilizes the variable moment of inertia (VMI) model, allowing for extraction of spin-dependent mixing strengths and amplitudes.