Sensitivity of the evaporation residue production to dynamical effects in highly fissile compound nuclei

Abstract We investigate the sensitivity of statistical model calculations of individual evaporation residue (ER) production on the nuclear shape evolution and viscosity. To this aim we analyze the de-excitation of the 217 Ac compound nucleus formed at the excitation energies between 36 and 90 MeV. We find a strong dependence of the calculated results on the nuclear dissipation and shape evolution, which make evaporation residues a useful tool for investigating dynamical effects. We indicate a new method of estimating the nuclear viscosity and claim that the statistical model interpretation of the ER's does not exclude high values for the viscosity parameter.