Nuclear molecule formation and time delay in collisions of nuclei with Z₁ + Z₂ ≥ 110

We investigated the formation of nuclear molecules and the occurrence of time delays in reactions of the superheavy systems ⁶⁴Ni + ²⁰⁷Pb (Z₁ + Z₂ = 110), ¹³²Xe + ²⁰⁸Pb (Z₁ + Z₂ = 136) and ²³⁸U + ²³⁸U (Z₁ + Z₂ = 184). In deep inelastic binary reactions of Ni + Pb and Xe + Pb we observed clear signatures for the formation of long-living molecule-like nuclear systems which rotate by large angles of 180 degree. The evolution of the nuclear molecules was accompanied by large energy dissipation and a strong deformation of the nuclear system. The results from the giant system U + U revealed striking similarities to the ones from Ni + Pb and Xe + Pb, showing that significant time delays still occur in the heaviest accessible systems. The experiments were performed at the velocity filter SHIP at GSI and at the VAMOS spectrometer at GANIL. (orig.)