SPIN M1 EXCITATIONS IN DEFORMED-NUCLEI FROM SELF-CONSISTENT HARTREE-FOCK PLUS RANDOM-PHASE-APPROXIMATION

We present a method to study spin magnetic dipole excitations in defor med nuclei within the quasiparticle random phase approximation based o n self-consistent Hartree-Fock mean fields and residual interactions d erived from the same effective two-body force. We perform a comprehens ive study covering different Skyrme forces and various mass regions, a nd discussing the role of the mean field and of the residual interacti on. An overall agreement with experimental data is obtained with the S G2 force. We study the systematics and the deformation dependence of t he spin M1 strength distributions of K-pi=1(+) excitations. It is foun d for the first time that the summed spin MI strength obeys a quadrati c dependence on deformation in the two isotope chains studied, Nd-142, Nd-146,Nd-148,Nd-150 and Sm-144,Sm-148,Sm-150,Sm-152,Sm-154.