Elastic and inelastic scattering for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ system: Target and projectile reorientation effects

Full angular distributions for elastic and inelastic scattering of ${}^{11}\mathrm{B}$ on ${}^{58}\mathrm{Ni}$ have been measured at different bombarding energies around the Coulomb barrier. Measurement and analysis with coupled-channel calculations have been performed for the first time for a system with the tightly bound ${}^{11}\mathrm{B}$ as projectile on a medium mass target. In these calculations, the real part of the interaction potential between nuclei was represented by a parameter-free double-folding potential. To avoid the use of an imaginary potential at the surface, several inelastic transitions of the projectile and the target have been included in the coupling matrix. The result of these coupled-channel calculations are in very good agreement with all experimental angular distributions. The most important result was the striking influence on the reaction mechanism of the ground-state-spin reorientation of the ${}^{11}\mathrm{B}$ nuclei.

Figure 1

Typical energy spectra for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ system measured at ${\theta }_{\mathrm{Lab}}=44.7^{\circ }$ and $E_{\mathrm{c}.\mathrm{m}.}=29.41$ MeV. The contributions of the excited states ${}^{58}\mathrm{Ni}$ ($2^{+}$, $4^{+}$, $2^{+}$) are indicated.

Figure 2

Elastic scattering angular distribution for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ system at $E_{\mathrm{c}.\mathrm{m}.}=21.01$ MeV in (a) linear and (b) logarithmic scales. The lines are results of coupled-channel calculations. See text for details.

Figure 3

Elastic scattering angular distributions for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ system at $E_{\mathrm{c}.\mathrm{m}.}=15.97$, 16.81, 17.65, 19.33, 20.17, and 29.41 MeV. The lines represent the CC calculations as indicated: dotted line is without any couplings, dashed lines couplings are only the target excited states, and solid lines are the full CCC including the reorientations for both target and projectile.

Figure 4

Inelastic scattering angular distributions for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ ($2^{+}$, 1.454) first excited state measured at $E_{\mathrm{c}.\mathrm{m}.}=15.97$, 16.81, 17.65, 19.33, 20.17, and 21.01 MeV. The solid lines are the results of the CC calculations.

Figure 5

Inelastic scattering angular distributions for the ${}^{11}\mathrm{B}+{}^{58}\mathrm{Ni}$ ($2^{+}$, $4^{+}$, $2^{+}$) first, second, and third excited states measured only at $E_{\mathrm{c}.\mathrm{m}.}=29.41$ MeV. The solid lines are the results of the CC calculations.