A projection operator formalism based on the Feshbach doorway approach is developed for low energy heavy ion scattering. An application to ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ is made with doorways taken as quasibound or virtual states of the reduced mass coupled to $2^{+}$ and $3^{-}$ vibrations. The elastic differential cross section at 90° is calculated and agrees rather well with experiment by producing both the gross and intermediate molecular structure.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ elastic scattering, $E=10-30\mathrm{}$ MeV c.m., projection operator intermediate structure theory, calculated $\sigma \left(90\mathrm{}°\right)$.

• Received 25 September 1979

DOI:https://doi.org/10.1103/PhysRevC.21.2126