Angular Distribution of Neutrons from theLi6(Li6, n)C11Reaction at 4.10 MeV

Angular distributions of neutrons from the ${\mathrm{Li}}^6({\mathrm{Li}}^6, n){\mathrm{C}}^{11}$ reaction have been measured at 4.1-MeV bombarding energy for all bound levels in ${\mathrm{C}}^{11}$ except the ground state. The 6.39-6.41-MeV doublet was not resolved. The angular distributions, generally, agree in relative magnitude and shape with those from analog states in the mirror reaction ${\mathrm{Li}}^6({\mathrm{Li}}^6, p){\mathrm{B}}^{11}$. This result is most easily understood by assuming that both reactions proceed predominately by compound-nucleus formation. The 8.43-MeV level in ${\mathrm{C}}^{11}$ is observed to decay by $\gamma$ emission even though it is unbound to $\alpha$-particle emission by 890 keV. This retardation of the $\alpha$ decay cannot be understood as being due to the Coulomb barrier alone.