  Herein, we investigated the channel coupling (CC) effect on the elastic
scatterings of lithium (Li) isotopes ($A =$ 6--9) for the $^{12}$C and
$^{28}$Si targets at $E/A =$ 50--60 MeV. The wave functions of the Li isotopes
were obtained using the stochastic multi-configuration mixing (SMCM) method
based on the microscopic-cluster model. The proton radii of the $^{7}$Li,
$^{8}$Li, and $^{9}$Li nuclei became smaller as the number of valence neutrons
increased. The valence neutrons in the $^{8}$Li and $^{9}$Li nuclei exhibited a
glue-like behavior, thereby attracting the $\alpha$ and $t$ clusters. Based on
the transition densities derived from these microscopic wave functions, the
elastic-scattering cross section was calculated using a microscopic
coupled-channel (MCC) method with a complex $G$-matrix interaction. The
existing experimental data for the elastic scatterings of the Li isotopes and
$^{10}$Be nuclei were well reproduced. The Li isotope elastic cross sections
were demonstrated for the $^{12}$C and $^{28}$Si targets at $E/A$ =53 MeV. The
glue-like effect of the valence neutrons on the Li isotope was clearly
demonstrated by the CC effect on elastic scattering. Finally, we realize that
the valence neutrons stabilized the bindings of the core parts and the CC
effect related to core excitation was indeed reduced.
