Signature inversion and deformation driving effects in 178Ir

High spin states in Ir-178 were investigated by means of in-beam gamma-ray spectroscopy techniques using the multidetector array GASP. Excited states of Ir-178 were populated through the Tb-159(Mg-24, 5n) fusion-evaporation reaction at E(Mg-24)=131-141 MeV. Fourteen rotational bands have been observed and their configurations discussed. Alignments, band crossing frequencies, dynamical and kinematical moments of inertia, and electromagnetic properties have been analyzed in the framework of the cranking model. Signature inversion in the pii(13/2)circle timesnui(13/2) and pih(9/2)circle timesnui(13/2) structures has been identified and interpreted in the framework of the particle rotor model with residual p-n interaction and variational moment of inertia. In bands involving the pii(13/2) orbital an increase in the deformation, relative to the other bands, has been found.