  The influence on the fusion process of coupling to collective degrees of
freedom has been explored. The significant enhancement of he fusion cross
setion at sub-barrier energies was understood in terms of the dynamical
processes arising from strong couplings to collective inelastic excitations of
the target and projectile. However, in the case of reactions where breakup
becomes an important process, conflicing model predictions and experimental
results have been reported in the literature. Excitation functions for sub- and
near-barrier total (complete + incomplete) fusion cross sections have been
measured for the $^{6,7}$Li + $^{59}$Co at the Vivitron facility and at the 8UD
Pelletron tandem facility using standard $\gamma$-ray techniques. The data
extend to medium-mass systems previous works exploring the coupling effects in
fusion reactions of both lighter and heavier systems. Results of
continuum-discretized coupled channel (CDCC) calculations indicate a small
enhancement of total fusion for the more weakly bound $^{6}$Li at sub-barrier
energies, with similar cross sections for both reactions at and above the
barrier. A systematic study of $^{4,6}$He induced fusion reactions with the
CDCC method is in progress. The understanding of the reaction dynamics
involving couplings to the breakup channels requires th explicit measurement of
precise elastic scattering data as well as yields leading to the breakup
itself. Recent coincidence experiments for $^{6,7}$Li + $^{59}$Co are
addressing this issue. The particle identification of the breakup products have
been achieved by measuring the three-body final-state correlations.
