Evidence Of Quasifission In The Hg-180 Composite System Formed In The Zn-68+Sn-112 Reaction

For the Zn-68 + Sn-112 reaction the Coulomb parameter Z(1)Z(2) is equal to 1500 that is close to the threshold value for the appearance of quasifission process. It was found that mass-energy distributions of the reaction fragments differ significantly from those obtained in the Ar-36 + Sm-144 reaction leading to the formation of the same composite system of Hg-180 at similar excitation energies of about 50 MeV. In the case of the reaction with Zn-68 ions, the mass distribution of fissionlike fragments has a wide two-humped shape with maximum yields at 70 and 110 u for the light and heavy fragments, respectively, instead of 80 and 100 u observed in the fission of Hg-180 formed in the Ar-36 + Sm-144 reaction. The difference is explained by an unexpectedly large contribution (more than 70%) of quasifission in the case of the Zn-68 + Sn-112 reaction. (C) 2021 The Authors. Published by Elsevier B.V.