Neutron evaporation as a probe for dynamical effects in heavy ion fusion reactions.

The compound nucleus 76Kr* was populated at the excitation energy of 75 MeV and angular momentum of 39 h in fusion reactions with two complementary, mass-symmetric (31P+45Sc) and mass asymmetric (12C+64Zn) entrance channels. The neutron evaporation spectra were measured and compared with the predictions of the statistical model calculations. The results for the mass-asymmetric reaction are found to be consistent with the predictions of the statistical model calculations. However, for the mass-symmetric reaction (31P+45Sc), the experimental spectra are found to be harder than the theoretical neutron spectra. The dynamical model calculations of Feldmeier show that the formation time for the compound nucleus for the symmetric system is relatively larger as compared to the asymmetric system. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]