Fission barriers, coupled-channel, and shell effects at the Coulomb barrier in the A similar to 190 mass region - art. no. 024607

A study of the role of coupled-channel effects in the enhancement of the po pulation of high-spin states was undertaken with the reactions Ca-48+Nd-142 and Se-80+Pd-110, near the Coulomb barrier, leading to the same compound n ucleus, Hg-190, at the same excitation energy. Statistical calculations wit h standard values for the level density parameters and fission barriers pre dict an enhancement of the high-spin population for the more mass-symmetric system, brought about by the coupling to inelastic channels in the fusion process. No enhancement was observed which we interpret as an inadequacy of the fission barriers used, and to the role of the shell corrections, in pa rticular those at the saddle point.