Collective and intrinsic structures in W-183

The structure of W-183 has been studied by employing the Yb-176(C-14, alpha 3n) reaction at 68 MeV. Five previously known rotational structure with on e-quasiparticle configurations have been extended to higher spin states, an d five new rotational bands with three- and five-quasiparticle configuratio ns and a gamma-vibration of a one-quasiparticle structure have been newly i dentified. In the nu 7/2(-)[503] and nu 11/2(+)[615] rotational structures, a signal of an admixture of an octupole vibrational structure has been obs erved in their in-band B(M1)/B(E2) ratios and g(K) factors. In the K-pi = 1 9(-) rotational band, a Coriolis effect on the nu 1/2(-)[510] neutron has b een identified. In all, 17 K-forbidden transitions have been observed. Ener gies of intrinsic states below 4 MeV have been calculated based on the Bloc ked BCS theory, and they are used in support of the configuration assignmen ts. (C) 1999 Elsevier Science B.V. All rights reserved.