A band crossing model with a smooth-cutoff representation of absorption effects is applied to the intermediate structure observed in elastic scattering of the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ system. The model is found to reproduce the experiment extremely well, which suggests strongly that the intermediate structure is a reflection of the existence of molecular resonances. The values of parameters in a smooth-cutoff representation of absorption effects are extracted by an analysis of the oscillatory fusion cross section.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, $6<~E_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~30$ MeV; ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=90\mathrm{}°$; calculated $\sigma \mathrm{}\left(E\right)\mathrm{}$. Resonance mechanism for Heavy Ion Reactions, absorption effects extracted from fusion data.

• Received 13 December 1978

DOI:https://doi.org/10.1103/PhysRevC.19.1365