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 O-16+U-238 and Ni-60+Sm-154 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 O-16+U-238 reaction are nearly the same while those are different for the 60Ni+154Sm 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 degrees < alpha(i) < 90 degrees (A) in comparison with that for angles 0 degrees < alpha(i) < 30 degrees (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 Kr-86 + Xe-130 and Sn-124 + Zr-92 reactions is explained by the difference between the B*(fus) values which depend on the nuclear shell corrections.
Role of the nuclear shell structure and orientation angles of deformed reactants in complete fusion
GIARDINA, Giorgio 42;MANDAGLIO, GIUSEPPE;
2006-01-01
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 O-16+U-238 and Ni-60+Sm-154 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 O-16+U-238 reaction are nearly the same while those are different for the 60Ni+154Sm 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 degrees < alpha(i) < 90 degrees (A) in comparison with that for angles 0 degrees < alpha(i) < 30 degrees (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 Kr-86 + Xe-130 and Sn-124 + Zr-92 reactions is explained by the difference between the B*(fus) values which depend on the nuclear shell corrections.Pubblicazioni consigliate
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