M1 spin excitations in deformed nuclei within a microscopic multiphonon approach - art. no. 054301

We adopt the quasiparticle-phonon nuclear model to compute the M1 strength distribution in the energy range 4-10 MeV in the deformed Sm-154. We show t hat the coupling with two-phonon configurations enhances considerably the f ragmentation of the M1 strength with respect to the random-phase approximat ion but not enough to reach a complete agreement with experiments. The resu lts obtained contribute also to shed light on the controversial properties of the M1 spectrum in this energy range.