Shape coexistence and multiparticle-multihole structures in Cd 110,112

From detailed spectroscopy of Cd110 and Cd112 following the β+/EC decay of In110,112 and the β- decay of Ag112, the presence of very weak decay branches from nonyrast states is revealed. In Cd112, 25+→04+ and 46+→25+ transitions are observed that yield B(E2;25+→04+)=34±15 W.u. and B(E2;46+→25+)=77±30 W.u., respectively, clearly indicating a collective structure. In Cd110, a weak decay branch from the 46+ level to the 25+ level is observed, and from a lifetime measurement following the (n,n′γ) reaction, B(E2;46+→25+)=55±14 W.u. is determined. A new branch is also observed for the decay of the 64+ level to the 46+ state, indicating that the sequence 25+, 46+, and 64+ forms part of a collective structure. The presence of 33+ and 52+ levels spaced between the previous sequence is highly suggestive of a γ band built on the 02+ shape-coexisting intruder state. The 04+ levels in Cd110,112,114 have preferred decays to the lowest 2+ members of the intruder bands, and for Cd114 a previous measurement had established an enhanced B(E2;04+→23+). The energy systematics of the 02+, 03+, and 04+ levels all display the characteristic parabolic-shaped pattern, suggesting that they are built on multiparticle-multihole proton excitations. The results are compared with beyond-mean-field calculations that reproduce qualitatively the observed levels and their decays and suggest that the 01+, 02+, 03+, and 04+ levels and the excited states built on them possess different deformations.