M1 excitation in Sm isotopes and the proton-neutronsdginteracting boson model

The magnetic-dipole scissors mode in spherical to deformed Sm isotopes is studied in terms of the proton-neutron sdg interacting boson model, providing a good agreement with recent experiment by Ziegler et al. The present calculation correctly reproduces the increase of M1 excitation strength in going from spherical to deformed nuclei. It is suggested that there may be $1^{+}$ states which do not correspond to the scissors mode but absorb certain M1 strength from the ground state.