ROLE OF THE NUCLEAR SHELL STRUCTURE AND ORIENTATION ANGLES OF DEFORMED REACTANTS IN COMPLETE FUSION

Abstract

The dependence of the capture and fusion excitation functions on the nuclear shell structure and initial orientation angles of the symmetry axis of the deformed projectile- and target-nucleus are explored by the dynamical model based on the dinuclear system concept and Langevin calculations. The fusion cross sections for 16 O +238 U and 60 Ni +154 Sm reactions obtained by averaging of the results for the all orientation angles are in good agreement with the experimental data. The capture and fusion cross sections for the 16 O +238 U reaction are nearly the same while those are different for the 60 Ni +154 Sm reaction due to presence of the hindrance to fusion as quasifission. The largest of the fusion cross section for the orientation angles of the reactants in the range 60° < αi < 90° (A) in comparison with that for angles 0° < αi < 30° (B) was explained by the increase of the quasifission contribution in the last case (B). The physical reason of this phenomenon is connected by the largest of the intrinsic fusion barrier B* fus in case (B) than that for the case (A). The observed difference between the excitation functions of evaporation residues for the 86 Kr +130 Xe and 124 Sn +92 Zr reactions is explained by the difference between the B* fus values which depend on the nuclear shell corrections.