The excitation functions were measured in the reaction of ²⁷Al+²⁷Al at incident energies from 114MeV to 127MeV in steps of 200 keV. The detection angles were continuously covered from 10° to 57° in the laboratory system. The energy autocorrelation functions of the dissipative fragments were analyzed by using different approaches. The nonself-averaging oscillations in the excitation functions were considered due to the angular momentum coherence and damping of the coherent nuclear rotation. The damping results from a quantum chaotic motion.