Investigation of properties of mixed symmetry states in Mo-94 and Ru-96

Mixed symmetry states in Mo-94 and recently also in Ru-96 were investigated in Koln, Stuttgart, and Yale. In order to understand the structure of the mixed symmetry states we made a shell model calculation. The resulting wave functions of low-lying J(pi) = 2(+) states for the near-spherical nucleus Mo-94 are analyzed with respect to their collectivity and the proton-neutron degree of freedom. The analysis uses the Q-phonon scheme applied to the shell model and it supports the mixed-symmetry interpretation of the interacting boson model for the multiphonon structure observed recently in Mo-94 by means of gamma-ray spectroscopy. Simple operators are obtained which generate major parts of the symmetric and mixed symmetry 2(+) states in Mo-94 when applied to the calculated ground state.