[en] The time-dependent cluster theory is applied to the description of the ground state spontaneous fission of 8Be and to the calculation of the fusion cross section at the sub-Coulomb barrier energies. The calculated decay width for a spontaneous fission is Γ (cal) ≅ 7.5 eV as compared to Γ (ex)=6.8 ± 1.7 eV found experiment. (author)