We present an experimental investigation of the energy spectra of the charged particles emitted from polycrystalline copper under argon and xenon cluster ion irradiation. Positive secondary particles have significantly lower energies than in the case of sputtering with atomic argon. The spectra of the charged particles emitted under xenon cluster bombardment are systematically narrower than the corresponding ones obtained under argon cluster bombardment. The observed regularities can be explained in terms of energy transfer form a cluster to the target.