Six ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ levels have been investigated in detail via the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}+\alpha$ channel between $6.9\le E_{\alpha }\le 10.2$ MeV. Level parameters for states at $E_x\left({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}\right)=10.264\mathrm{}\pm 0.008, 11.077\pm 0.008, 11.259\pm 0.008, 11.552\pm 0.008,12.237\pm 0.008, \mathrm{and} 12.390\pm 0.008$ MeV have been extracted from $\gamma$ decay properties and phase shift analysis of the elastic scattering. With the exception of the 11.552 and 12.39 MeV states, these levels display primarily $T=1\mathrm{}$ characteristics. In addition to some previously reported $T=0\mathrm{}$ states, several other weak $\gamma$ decaying resonances were observed at 11.97 ± 0.04, 12.05 ± 0.04, and 12.49 ± 0.02 MeV but were not studied in detail. Charge dependent matrix elements (4-120 keV) for isospin mixing of $T=1\mathrm{}$ states with nearby $T=0\mathrm{}$ states were estimated from the measured level parameters.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha ,{\alpha }_0){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha ,{\gamma }_{0,1,2}){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha ,{\alpha }_2{\gamma }_{6.13}){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, $E_{\alpha }=6.9\mathrm{}-10.2$ MeV; measured $\sigma (E,\theta )$. Deduced ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ level parameters, $J$, $\pi$, $T$, $\gamma$-branching ratios, ${\Gamma }_{\gamma }$, $\Gamma$, $E_R$. Isospin mixing, charge dependent Hamiltonian, IAS.

• Received 7 September 1977

DOI:https://doi.org/10.1103/PhysRevC.17.1034