Sub-Coulomb Transfer Reactions on Actinide Nuclei

Surprisingly large discrepancies have been found between some measured and calculated cross sections for sub-Coulomb transfer reactions on several actinide nuclei. The calculated cross sections of strongly excited states with $J\ge \frac{7}{2}$ are generally too small by a factor of 2-3, such as Siemssen and Erskine had observed in the reaction ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}\mathrm{}(d,p)\mathrm{}{}_{}{}^{183}{}_{}{}^{}\mathrm{W}$. A few exceptions to the above rule are found for weakly excited states. In the present study, the use of very low bombarding energies results in an important simplification of the analysis in that the calculated cross sections then are insensitive to uncertainties in the optical-model parameters. The present results suggest that the discrepancy in cross sections probably results from inadequate treatment of the asymptotic tail of the bound-state wave function rather than from neglect of inelastic scattering processes in the incoming and outgoing waves.