Elastic scattering of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Li</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>6</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Zn</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>64</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>at near-barrier energies

Elastic-scattering angular distributions for the $^{6}\mathrm{Li}+^{64}\mathrm{Zn}$ system were measured at eight beam energies from below to above the Coulomb barrier, $12.0\ensuremath{\leqslant}{E}_{\mathrm{lab}}\ensuremath{\leqslant}22.0$ MeV. The experimental data were analyzed within the optical model to study the energy dependence of the interaction potential and to obtain total reaction cross sections. The results obtained using several optical model potentials show similar behavior. The energy dependence of the strengths of the real and imaginary potentials suggests the presence of the breakup threshold anomaly. It is shown that the extracted energy dependence of the interaction potential at sub-barrier energies is very sensitive to possible experimental errors.