The excitation function for the complete fusion of ${}^9\mathrm{Be}$$+$${}^{89}\mathrm{Y}$ has been measured at near-barrier energies, and the barrier distribution has been extracted from the fusion data. Coupled-channels calculations have been carried out to understand the effect of coupling of both the projectile and target excitations on the above quantities. The complete fusion cross sections, especially at above-barrier energies, have been found to be suppressed by ($20\pm 5$)% compared to the ones predicted by the coupled-channels calculations that do not include the couplings to the projectile continuum, indicating the loss of flux from the entrance channel before fusion. This conclusion is also supported by a considerable incomplete fusion cross section observed for this system. Fusion measurements for two more systems have been carried out, namely, for ${}^4\mathrm{He}$$+$${}^{93}\mathrm{Nb}$ and ${}^{12}\mathrm{C}$$+$${}^{89}\mathrm{Y}$, which involve tightly bound projectiles and form compound nuclei nearby to that formed in ${}^9\mathrm{Be}$$+$${}^{89}\mathrm{Y}$ fusion. Comparison of the fusion data obtained for all three systems further confirms the suppression of complete fusion in the ${}^9\mathrm{Be}$$+$${}^{89}\mathrm{Y}$ system. Systematics of the suppression factor observed for ${}^9\mathrm{Be}$ induced fusion in different mass targets is discussed.

• Received 20 August 2010

DOI:https://doi.org/10.1103/PhysRevC.82.044608