Description of large angleLi6+Ca40scattering from 26 to 34 MeV using double-folded andα+dcluster potentials

Abstract

New elastic scattering data are reported for $^{6}\mathrm{Li}$ + $^{40}\mathrm{Ca}$ at 26 and 30 MeV, and inelastic data at 30 MeV. The measurements at 30 MeV were taken to provide a complete angular distribution at this energy and showed that previously published large angle data at 30 MeV are incorrectly normalized and must be multiplied by 0.65. The new angular distribution at 26 MeV displays enhanced large angle cross sections as has also been previously observed at 30 and 34 MeV. Double-folded or cluster potentials are able to describe the elastic scattering of $^{6}\mathrm{Li}$ + $^{40}\mathrm{Ca}$ over the energy range 26-34 MeV, including the large angle oscillations. No special property is required to explain the large angle behavior other than weak absorption. The double-folding model has also been used to determine deformation lengths for the first ${2}^{+}$, ${3}^{\ensuremath{-}}$, and ${5}^{\ensuremath{-}}$ states in $^{40}\mathrm{Ca}$. The values for the ${2}^{+}$ and ${3}^{\ensuremath{-}}$ states agree well with those found from electron, $^{9}\mathrm{Be}$ and $^{11}\mathrm{B}$ inelastic scattering, while the value for the ${5}^{\ensuremath{-}}$ state is a factor of 2 smaller.NUCLEAR REACTIONS $^{40}\mathrm{Ca}$($^{6}\mathrm{Li}$,$^{6}\mathrm{Li}$)$^{40}\mathrm{Ca}$, $E=26$ MeV, ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=9\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}161\ifmmode^\circ\else\textdegree\fi{}$; $^{40}\mathrm{Ca}$($^{6}\mathrm{Li}$, $^{6}\mathrm{Li}$)$^{40}\mathrm{Ca}$* elastic and ${3}^{\ensuremath{-}}$, ${2}^{+}$, ${5}^{\ensuremath{-}}$ $E=30$ MeV, ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=9\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}78\ifmmode^\circ\else\textdegree\fi{}$; measured $\ensuremath{\sigma}(\ensuremath{\theta})$. Double-folding model, cluster folding model, deduced optical model parameters; DWBA, deduced deformation lengths at 30 MeV.