Decay of 1+ states as a new probe of the structure of 0+ shape isomers

The nuclides 98Mo and100Mo have been studied in photon-scattering experiments by using bremsstrahlung produced from electron beams with energies from 3.2 to 3.8 MeV. Six dipole transitions in 98Mo and 19 in 100Mo were observed for the first time in the energy range from 2 to 4 MeV. A specific feature in both nuclides is the deexcitation of one state with spin J = 1 to the 0+ ground state as well as to the first excited 0+ state, which cannot be explained in standard models. We present a model based on one-particle-one-hole excitations, which allows us to deduce the mixing amplitudes for the two 0+ shape-isomeric states from the experimental ratio of the transition strengths from the J = 1 state to the 0+ ground state and to the 0+ excited state.