  The isospin-dependent quantum molecular dynamics (IDQMD) model is used to
study the total reaction cross section $\sigma_R$. The energy-dependent Pauli
volumes of neutrons and protons have been discussed and introduced into the
IDQMD calculation to replace the widely used energy-independent Pauli volumes.
The modified IDQMD calculation can reproduce the experimental $\sigma_R$ well
for both stable and exotic nuclei induced reactions. Comparisons of the
calculated $\sigma_R$ induced by $^{11}Li$ with different initial density
distributions have been performed. It is shown that the calculation by using
the experimentally deduced density distribution with a long tail can fit the
experimental excitation function better than that by using the
Skyrme-Hartree-Fock calculated density without long tails. It is also found
that $\sigma_R$ at high energy is sensitive to the long tail of density
distribution.
