[en] Fusion excitation functions for the systems ⁴⁰Ar+sup(112,116,122)Sn and ⁴⁰Ar+sup(144,148,154)Sm have been determined, covering cross sections ranging from several hundred mb down to the μb level. The data show a pronounced correlation of the subbarrier behaviour with low-energy collective properties of the nuclei involved and are well reproduced by simplified coupled channels calculations coupling fusion to inelastic channels. Possibilities to parameterize the data in terms of a simple dynamic barrier fluctuation phenomenon are discussed and result in the prediction of remarkably diffuse partial wave distributions above the barrier. This is shown to be important for the analysis of deexcitation phenomena following fusion reactions. (orig.)