High-spin resonant states in 16O

Abstract

α+12C elastic scattering in the energy range Ec.m. = 21.15–26.625 MeV is analyzed by the optical model with parity-dependent potential. The characteristic features enhanced by Coulomb scattering appear to be reproduced. The volume integral of the potential, which indicates the net strength of interactions between nuclei, seems to be consistent with those from other studies and it gives a smooth energy variation from high to low energies. The 9− state is found to occur at Ec.m. ≈ 23.0 MeV, corresponding to the excitation energy Ex ≈ 30.2 MeV. It is possible that the 8+ resonance was observed at Ex ≈ 29 MeV with a large width. The α+12C rotational band can survive even at high excitation energies. The rotational band starting from the 0+2 state (Ex = 6.05 MeV) is confirmed to have N = 8; the odd-parity band, N = 9.