[en] The fusion of the massive systems ¹¹⁰Pd+¹⁰⁴Ru and ¹¹⁰Pd+¹¹⁰Pd was uniquely identified by observing the α decay of the evaporation residues. The observed distribution of the fusion cross section on the different evaporation-residue channels is in clear contradiction to calculations based on the compound-nucleus model. As a possible explanation the precompound of α particles is proposed. (orig.)

[en] Published in summary form only

[en] For the compound nucleus ¹⁷⁹Au formed at an excitation energy of 26 MeV in the fusion reaction ⁹⁰Zr+⁸⁹Y, the energy spectra of promptly emitted protons, α particles and γ rays were measured in concidence with the evaporation residues. On the basis of the measured total decay energy, the 1 p and 1 α decay channels were separated from all other evaporation-residue channels. The energy spectra and absolute cross sections, together with previously measured excitation functions for various decay channels, are successfully described by statistical-model calculations with the Monte Carlo code CODEX. (orig.)