Quadrupole and monopole transition properties of 02+ in Gd isotopes

The longstanding problem of characterization of the 0(2)(+) states in Gd isotopes is revisited by adopting the Nilsson+BCS mean field and the random-phase approximation. The interband electric quadrupole transition strengths varying almost two orders of magnitude are nicely reproduced at the same time as other observables. These results indicate that the 0(2)(+) states, in particular those in lighter isotopes, are well described as beta vibrations excited on top of deformed ground states without recourse to the shape-coexistence picture.