Fusion of the Borromean nucleus Be 9 with a Au 197 target at near-barrier energies

To probe the role of the intrinsic structure of the projectile on subbarrier fusion, measurement of fusion cross sections has been carried out in a $^{9}\mathrm{Be} + ^{197}\mathrm{Au}$ system in the energy range ${E}_{\mathrm{c}.\mathrm{m}.}/{V}_{B}\phantom{\rule{4pt}{0ex}}\ensuremath{\approx}$ 0.82 to 1.16 using off-beam $\ensuremath{\gamma}$-counting method. Measured fusion excitation function has been analyzed in the framework of the coupled-channel approach using CCFULL code. It is observed that the coupled-channel calculations, including couplings to the inelastic state of the target and the first two states of the rotational band built on the ground state of the projectile, provide a very good description of the subbarrier fusion data. At above-barrier energies, the fusion cross section is found to be suppressed by $\ensuremath{\approx}39(2)%$ as compared to the coupled-channel prediction. A comparison of reduced excitation function of $^{9}\mathrm{Be} + ^{197}\mathrm{Au}$ with other $x + ^{197}\mathrm{Au}$ shows a larger enhancement for $^{9}\mathrm{Be}$ in the subbarrier region amongst $Z=2--5$ weakly and tightly bound projectiles, which indicates the prominent role of the projectile deformation in addition to the weak binding.