The role of orientation of nucleus symmetry axis in fusion dynamics

The dependence of the fusion excitation function on the orientation angles of the symmetry axis of deformed projectile- and target-nucleus relative to the beam direction is studied. The averaged over all orientations values of the fusion-fission cross sections obtained for 16O + 238U and 60Ni + 154Sm reactions are compared with the experimental data. The capture and fusion cross sections for the 16O + 238U reaction are nearly the same while those are different for the 60Ni + 154Sm reaction due to sufficient contribution of the quasifission events. The large values of the fusion cross section are obtained in the range 60°<αi<90° of the orientation angles of the projectile- and target-nucleus. This phenomenon is explained by the dependence of the intrinsic fusion and quasifission barriers on the orientation angles of reactants.