Coherence energies extracted from excitation functions and angular distributions for the fragments emitted in the a 9 F _}_ 63Cu reaction, measured in the range 01a b = l0 ~ to 120 ~ at incident energies between 100 to 108 MeV (lab.), were compared to the Kun model of dissipative collisions. An overall agreement was found for the angular distributions at forward angles. The general behavior of coherence energies was also properly described and interaction times were deduced.