  The light weakly-bound nucleus $^7$Li is studied within a dicluster
$\alpha+t$ picture. Different observables obtained within our simple model are
compared with previous calculations and experiments showing good agreement. In
particular we calculate dipole and quadrupole electromagnetic response to the
continuum. The energy distribution of B(E$\lambda$) values are consistent with
the energy weighted molecular sum rule and display a sizable contribution of
non-resonant character arising from the weak binding property. The
corresponding form factors for excitations to the continuum are used in a
semiclassical coupled channel scheme to get estimates for the break-up cross
section in a heavy ion reaction. The nuclear contribution is found to play an
important role in the process for bombarding energies around the Coulomb
barrier. The masses and charges ratios of the two clusters are shown to lead to
features of the cluster halo that may significantly differ from the one usually
associated with one-nucleon haloes.
