Total reaction cross sections for the radioactive nucleus Li-8 on Zr-90
are reported at the near-barrier energies of 18.5 and 21.5MeV, derived
from quasi-elastic scattering measurements. An analysis of the
quasi-elastic scattering results is performed within an optical model
framework using the BDM3Y1 interaction and total reaction cross sections
are deduced. These quantities, appropriately reduced, are compared with
previous data obtained in elastic scattering measurements with well and
weakly bound projectiles on various targets and a formula for predicting
total reaction cross sections with an uncertainty of similar to 20% is
obtained. Further on, the ratios of direct to total reaction cross
sections are estimated for 6,8 Li on various targets and are compared
with CDCC or CRC calculations. The energy dependence of the optical
potential is also discussed
