The excitation of the giant dipole resonance induced by fusion reaction is studied with $N/Z$ asymmetry in the entrance channel. The time dependent Hartree-Fock solution exhibits a strong dipole vibration which can be associated with a giant vibration along the main axis of the deformed compound nucleus. This dipole motion appears to be nonlinearly coupled to the shape oscillation, leading to a strong modulation of its frequency. These phenomena can be detected in the gamma-ray emission from hot compound nuclei.

• Received 15 December 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.2971