Vibrational and intruder structures in [Formula Presented]

Decay properties of multiphonon quadrupole vibrational states and intruder structures in [Formula Presented] have been examined with the [Formula Presented] reaction. γ-ray excitation functions, angular distributions, and [Formula Presented] coincidences have been measured. Lifetimes of many levels were determined with the Doppler-shift attenuation method, exposing the degree of collectivity of the intruder structure and the three-phonon states. In combination with other recent results, this new information reveals that the intruder picture is well supported in the Cd nuclei. However, a puzzle not present in the lighter Cd nuclei emerges in [Formula Presented] strong configuration mixing between intruder and multiphonon vibrational excitations cannot describe the observed decays of the lowest [Formula Presented] excited states.