The ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}(\alpha ,2\mathrm{}\alpha ){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ reaction has been measured at symmetric and asymmetric sets of angles at $E_{\alpha }=78.6\mathrm{}$ MeV. The data indicate that quasifree $\alpha -\alpha$ scattering and, consequently, $\alpha$ clustering plays a dominant role for pairs of angles favoring quasifree scattering. The data have been compared with the plane-wave impulse approximation using a radial cutoff. This calculation does not give a good fit to data for non-quasifree angles. The reaction goes predominantly to the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ground state with a small yield to the 6.92-7.12-MeV doublet in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$.

[NUCLEAR REACTIONS ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}(\alpha ,2\mathrm{}\alpha ){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, $E=78.6\mathrm{}$ MeV; measured ($E_L,E_R,{\theta }_L,{\theta }_R$). PWIA analysis.]

• Received 7 September 1973

DOI:https://doi.org/10.1103/PhysRevC.9.581