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

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