TREATMENT OF COMPETITION BETWEEN COMPLETE FUSION AND QUASI-FISSION INCOLLISIONS OF HEAVY-NUCLEI

A model of competition between complete fusion and quasifission channe ls in fusion of two massive nuclei is extended to include the influenc e of dissipative effects on the dynamics of nuclear fusion. By using t he multidimensional Kramers-type stationary solution of the Fokker-Pla nck equation, the fusion rate through the inner fusion barrier in mass asymmetry is studied. Fusion probabilities in symmetric Zr-90+Zr-90, Mo-100+Mo-100, Pd-110+Pd-110, Xe-136+Xe-136, almost symmetric Kr-86+Xe -136 and Pd-110+Xe-136 reactions are calculated. An estimation of the fusion probabilities is given for asymmetrical Ni-62+Pb-208, Zn-70+Pb- 208, Se-82+Pb-208, and Ca-48+Pu-244 reactions used for the synthesis o f new superheavy elements. (C) 1997 Elsevier Science B.V.