Study of quasi-elastic scattering for the system 7 Li + 159 Tb at around barrier energies

Systematic experimental and theoretical studies of the effect of coupling of collective degrees of freedom (like inelastic excitation, rotation, surface vibration and transfer of nucleons) on the fusion process of tightly bound nuclei at energies around the Coulomb barrier have been studied and reported in literatures[1, 2] in the last two decades. The fusion barrier distribution function (Dfus) can be extracted directly from fusion excitation function. Dfus is very sensitive to the coupling scheme and can be used to understand the consequence of these couplings on fusion reaction. The effect of the breakup of weakly bound light nuclei on the fusion process is a subject of current experimental and theoretical investigations due to the recent availability of radio-active ion beams. As second derivative of cross sections are involved in extracting fusion barrier distribution function (Dfus), it is essential that a high-precision measurement of fusion excitation function is done. But it is still very difficult to perform high-precision measurements of fusion cross sections with radioactive beams. An alternative method for obtaining information about barrier distribution is the derivation of backward angle quasi-elastic scattering (QES) barrier distribution.The barrier distribution extracted from quasi-elastic cross-section ( Dqel ), involves the first derivative of the ratio of QEL scattering cross section to the Rutherford scattering cross section with respect to