Description of collective magnetic states within a spherical single particle basis

A many-body Hamiltonian comprising pairing, quadrupole-quadrupole and spin-spin interactions is treated within a projected spherical basis with the aim of describing the detailed structure of the magnetic states of orbital and spin-flip nature in ^144,148-154Sm. The mean field for the single-particle motion takes care of the volume conservation of a phenomenological core, which results in having a complex dependence on deformation for single-particle energies. Several experimental features like the total orbital and total spin strengths, the shape of the orbital strength distribution, the hump structure of the spin strength distribution, the quadratic dependence of the orbital strength on nuclear deformation, and the saturation effect of the orbital strength with respect to the Casten factor P are very well described within a quasiparticle random-phase approximation formalism. A comparison of the present results with those obtained in some previous treatments is also given.