DESCRIPTION OF ORBITAL AND SPIN EXCITATIONS WITHIN A PROJECTED SPHERICAL SINGLE-PARTICLE BASIS

Orbital and spin excitations in even Sm isotopes have been studied mic roscopically in a quasiparticle random phase approximation approach fo rmulated in the laboratory frame using a projected spherical single-pa rticle basis which reproduces the Nilsson level scheme to a good appro ximation. The orbital magnetic dipole excitations are found to fall be low 4 MeV with a summed strength which follows closely the observed de formation quadratic law. The M1 spin strength is found to be strongly fragmented over a range of 4 to 10 MeV and, in the case of the well de formed Sm-154 isotope, distributed so as to reproduce the double hump pattern observed experimentally.