Angular distributions for the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$${+}^{13}$C elastic and inelastic scattering have been measured at a ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ bombarding energy of 50.46 MeV over an angular range from 10° to 170° c.m. Besides the ground state of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, the 3.68 MeV ${\mathit{J}}^{\mathrm{\pi }}$=3/$2^{\mathrm{-}}$ and the 7.55 MeV ${\mathit{J}}^{\mathrm{\pi }}$=5/$2^{\mathrm{-}}$ levels are strongly populated. The enhancement of the backward cross section is clear evidence that the process is dominated by the exchange of an α particle between two identical ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ cores. The experimental relative integrated cross sections are fairly well reproduced by distorted wave calculations using an α-cluster form factor and the shell-model spectroscopic strengths of Kurath.

• Received 6 November 1989

DOI:https://doi.org/10.1103/PhysRevC.41.2425