Thermal properties and dynamics of hot nuclei

The heat capacities and the dynamics of hot medium mass nuclei have been explored by studies of light particle emission. The variation in heat capacity with temperature, expressed in terms of an effective Fermi gas level density parameter appropriate to the statistical description of nuclear de-excitation, corresponds to a decrease in a from A/8 to A/13 as the excitation energy increases from 1 to 2 MeV/nucleon. This result is compared to recent theoretical predictions. An apparent sudden change in the heat capacity observed at slightly higher excitation energies per nucleon is also discussed. Prescission and post-scission particle multiplicities and temperatures in coincidence with evaporation residues and fission fragments provide further information on the decay dynamics of hot nuclei. Possible means of isolating presaddle emission and of determining the temperature dependence of the fission barrier are discussed.