Towards spectral pattern of spin polarized sodium clusters: The example ofNa-12

We investigate spin modes in the ground state and the polarized first isome r of the Na-12 cluster describing the valence electrons in time-dependent l ocal-spin-density approximation (TDLSDA) and the detailed ionic background using local pseudopotentials. The spin modes show a collective redshift com pared to the unperturbed particle-hole excitations. They are strongly fragm ented and the average energy of the modes along the principal axes are rela ted to the underlying geometry (triaxial or axially symmetric). For the pol arized isomer, we find significant cross talk between the spin modes and th e dipole plasmon, which hints at a possible spectroscopic identification.