MULTIDIMENSIONAL SEMIMICROSCOPIC MODEL OF THE SUBBARRIER FUSION OF HEAVY-IONS

A semimicroscopic model is constructed for describing the subbarrier f usion of heavy ions. The model takes into account deformations undergo ne by ions as they pass under the barrier. It is shown that fusion is accompanied by changes in the shape of ions, which are slightly oblate in the vicinity of the outer turning point and strongly prolate in th e vicinity of the inner turning point. At the same time, the distance between the centers of mass of ions changes insignificantly. In this m odel, energy dissipation in ion collisions before the outer turning po int is taken into account. This dissipation is associated with the exi t of ions from the fusion channel as the result of energy transfer to other degrees of freedom. The potential energy of ion interaction is c alculated with allowance for shell corrections. Pairing forces are tak en into account in the calculation of the microscopic adiabatic cranki ng mass parameter. The cross section and mean angular momentum of an e vaporation residue formed in ion fusion are calculated with allowance for the possible fission of a compound nucleus. It is found that the m ean angular momentum of the compound nucleus is saturated at energies above the barrier when the fission of the compound nucleus formed foll owing the fusion of heavy ions and particle emission is taken into acc ount. The model describes well the experimental energy dependences of the cross sections and mean angular momenta of evaporation residues.