Determination of the level structure of even-even Gd-156 by using the (SM)-S-154 (alpha,2n gamma) reaction

Abstract

High-spin states of Gd-156 were populated by using the Sm-154(alpha,2ngamma)Gd-156 reaction at E-alpha = 33 MeV. gamma-gamma coincidence, E-gamma singles, the excitation function, and the DCO ratios were measured. Medium-spin levels up to J = 18 were observed in the present work. The proposed level scheme was classified into six rotational bands with five positive-parity bands and one negative-parity band. Two-band mixing between the ground-state band and the beta or gamma band showed that the mixing parameters Z(beta) and Z(gamma) were somewhat smaller than the nominal mixing parameters for rare-earth nuclei. Finally, the present level scheme was compared with that predicted by using the interacting boson approximation model.