Shape Coexistence in the Neutron-Deficient Even-EvenHg182−188Isotopes Studied via Coulomb Excitation

Abstract

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.

Shell-model-based deformation analysis of light cadmium isotopes

“…In Figure 4 the deformation parameter γ is shown for the ground state as a function of increasing mass number A(N ). Together with the information of Figure 2, one notices that γ is increasing with N , starting at a slightly prolate deformation in 98 Cd of γ = 7.8°. In 108 Cd the γ value reaches a value 17.5°and thus is approaching the maximal triaxiality value of 30°, a value that separates the regions of prolate and oblate deformation.…”

“…We notice, that no β value could be derived for the 0 + 2 state in 98 Cd using the method of section III A in this LSSM model space. The nucleus 98 Cd has a closed neutron shell and two proton holes within the 1g 9/2 and 2p 1/2 orbitals, which can couple to form excited states within the used model space.…”

“…These methods have been used in a large number of recent papers (in particular in the region of the Ge, Kr, Mo, Ru and Pd nuclei [90][91][92][93][94][95], as well as in the much heavier Pb mass region (W, Os, Pt, Hg, Po isotopes) [96][97][98][99][100][101].…”

“…The procedure used is to fix the proton effective charge e π fitting the theoretical B(E2) value for the 8 + 1 → 6 + 1 transition to the known experimental value in 98 Cd [8]. Having fixed this value, the neutron effective charge e ν was fixed by comparing the experimentally known and theoretically calculated B(E2) values for the 2…”

“…The nucleus 98 Cd has a closed neutron shell and two proton holes within the 1g 9/2 and 2p 1/2 orbitals, which can couple to form excited states within the used model space. The 98 Cd E2 transition scheme therefore consists mainly of an yrast band, characterized by seniority ν = 2 excitations, with the two proton holes placed in the 1g 9/2 orbital for each state of the band.…”