PARTICLE EMISSION BUT ALSO FISSION IN THE DECAY OF VERY EXCITED NUCLEI

An extension of the statistical model for the study of very excited nuclei is presented. The temperature and angular momentum dependences of the fission barriers are obtained in a liquid drop picture. It provides us with the relevant potential landscapes for some collective variables which evolve during the decay according to a generalized transport equation. The light particle evaporation during the fast fission process and the fission after compound nucleus formation is calculated and compared with some available experimental results, e.g. for 40Ar + 238U at 27 MeV/u. The competing process of particle emission (cooling) doring the thermal equilibrium prevents a complete transfer of excitation energy along the whole evolution of the system. Such nuclei should be called warm instead of hot