Proton-neutron structure of collective excitations in $\chem{^{94}Mo}$

Resulting wave functions of low-lying $J^\pi = 2^+$ states from a recent shell model calculation for the near-spherical nucleus $^{94}$Mo 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 $^{94}$Mo by means of $\gamma$-ray spectroscopy. Simple operators are obtained which generate major parts of the symmetric- and mixed-symmetry $2^+$ states in $^{94}$Mo when applied to the calculated ground state