The differential cross section for the excitation of the unbound $3^{+}$ (2.18 MeV) state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ was measured by scattering a 227 MeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ beam from a ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ target. Additionally, the cross section for the $3^{\mathrm{-}}$ (3.74 MeV) state in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ was measured at the same center-of-mass energy by scattering a 34 MeV ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ beam from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. The cross section for excitation of the $3^{+}$, 2.18 MeV state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ is 3–5 times larger than that of the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ $3^{\mathrm{-}}$ state. The present data and previously measured elastic scattering data have been analyzed in the framework of both distorted-wave Born approximation and coupled channels calculations, using double folded real potentials, to determine the influence of the inelastic states on the elastic scattering cross section. We find that the elastic scattering is very sensitive to coupled channels effects arising from the $3^{+}$ state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$.

• Received 1 June 1987

DOI:https://doi.org/10.1103/PhysRevC.36.1865