Effects of Isospin Equilibrium on Cold Fusion of Superheavy Nuclei

The neutron flow model predicts that neutrons start to flow freely between the approaching nuclei ⁵⁸Fe and ²⁰⁸Pb at s=3fm, a length in which the effective surfaces of these nuclei are 3fm apart. As a result of neutron flow, the N/Z value rapidly reaches an equilibrium distribution. Meanwhile the system, originally in the fusion valley, is injected into the asymmetric fission valley. The dynamic process of the composite nucleus in the asymmetric fission valley is treated with a two-parameter Smoluchowski equation. It is shown that the probability to overcome the asymmetric fission barrier and to achieve compound nucleus configuration, hence the fusion cross section is obviously suppressed due to the effect of isospin equilibrium.