Measurement of elastic ${}^{16}\mathrm{O}{+}^{12}\mathrm{C}$ scattering at $E_{\mathrm{lab}}=132\mathrm{}\hspace{0.5em}\mathrm{MeV}$ has been performed over the angular range $6°<{\Theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}<125\mathrm{}°$, which covers both the diffractive and refractive regions. A prominent minimum has been observed at ${\Theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}\approx 86°$, which can be identified as an Airy minimum preceding the rainbow maximum. It thus provides the first clear experimental evidence for the refractive (rainbow) scattering pattern in the ${}^{16}\mathrm{O}{+}^{12}\mathrm{C}$ system. This Airy structure can be well described by discrete sets of optical potentials with a relatively weak absorption and a deep real potential. Candidates for the realistic family of ${}^{16}\mathrm{O}{+}^{12}\mathrm{C}$ optical potentials at $E_{\mathrm{lab}}=132\mathrm{}\hspace{0.5em}\mathrm{MeV}$ are discussed; those include the semimicroscopic potential given by the double-folding model.

• Received 24 November 1997

DOI:https://doi.org/10.1103/PhysRevC.57.1797