Valence mirror nuclei

A comparison of examples of 'valence mirror nuclei' (nuclei of the type N=82, Z=60+k and N=60+k, Z=50) 142Nd (144Sm) and 110Sn (112Sn) reveals a remarkable similarity of the level energies of the yrast and yrare states. This is valid for states up to an energy of 5 MeV which have an unbroken magic core for the other kinds of particle.