Identification of collective bands in neutron-rich 108Ru nucleus

Through measuring high-fold prompt γ-ray coincidence events following the spontaneous fission of 252Cf with the Gammasphere detector array, new level scheme in the very neutron-rich 108Ru nucleus has been established. The ground-state band, the one-phone γ-vibrational band and a two-quasi-particle band have been confirmed and expanded. Besides, a two-phonon γ-vibrational band has been identified. From cranked shell model calculations, 108Ru nucleus may have triaxial deformation with parameters β2=0.29, γ=-22 degree and the band crossing in the yrast band is due to the alignment of two h11/2 neutrons. The possible configurations for the two-quasiparticle collective band were also discussed. (authors)