Disagreement between capture probabilities extracted from capture and   quasi-elastic backscattering excitation functions
  Experimental quasi-elastic backscattering and capture (fusion) excitation functions are usually used to extract the s-wave capture probabilities for the heavy-ion reactions. We investigated the $^{16}$O+$^{120}$Sn,$^{144}$Sm,$^{208}$Pb systems at energies near and below the corresponding Coulomb barriers and concluded that the probabilities extracted from quasi-elastic data are much larger than the ones extracted from fusion excitation functions at sub and deep-sub barrier energies. This seems to be a reasonable explanation for the known disagreement observed in literature for the nuclear potential diffuseness derived from both methods. 
V.V.Sargsyan, G.G.Adamian, N.V.Antonenko, and R.P.S.Gomes
nucl-th