Collective structures and smooth band termination in 109Sn

Six rotational bands up to energies Ex = 24.7 MeV and spins Jπ=(79/2-) have been identified in 109Sn using the GAMMASPHERE γ-detector array. Four of the bands show smoothly decreasing dynamic moments of inertia at rotational frequencies ℎω>0.6 MeV. The bands arise at medium spins from a coupling of a valence d5/2, g7/2 or h11/2 neutron to the deformed 2p2h proton excitation of the Z=50 core 108Sn. At very high ℎω these bands show the typical behaviour of smoothly terminating bands, i.e. a gradual alignment of the angular momenta of the valence particles and holes corresponding to a transition from high collectivity to noncollective states. (orig.)