STATISTICAL DESCRIPTION OF THE DECAY OF NUCLEI HAVING 2 CLASSES OF EXCITED-STATES

The decay of heavy nuclei is discussed in the framework of the statist ical theory using the double-humped model for the fission barrier. It is shown that the existence of two classes of excited states in such n uclei is reflected in many observables, such as the decay law, the cro ss sections, the partial decay probabilities and the time dependence o f decay yields. It is demonstrated that: (i) the decay time in the fis sion channel is different from that in any other channel; (ii) the par tial decay probabilities depend on the initial conditions under which the compound nucleus is formed; (iii) the lifetime of the second-well states influences the evaporation spectra. It is also shown that the d ecay time characteristics of nuclei having two classes of excited stat es contain information on the strongly deformed excited states in the second well, like their density, and the depth of the second well itse lf.