A simple compact correlation of the energies of the lowest $0^{+}$ excitation with the yrast energy ratio $R_{4/2}(\mathrm{g}.\mathrm{s}.\mathrm{})\equiv {E(4\mathrm{}}_1^{+}{)/E(2\mathrm{}}_1^{+})$ is found to characterize all collective nuclei, regardless of structure. This correlation can be reproduced by interacting bosom approximation calculations. Collective signature observables for the states based on $0_2^{+}$ excitations indicate a different structure than for the ground state configuration but systematic inconsistencies in their global behavior and discrepancies with calculations prevent a definite interpretation.

• Received 24 April 2001

DOI:https://doi.org/10.1103/PhysRevC.64.057301