Alpha cluster states in 16O

A very successful cluster-core model for the rotational bands of light nuclei has been extended to treat excited core states. The resulting coupled-channels problem has been solved for the 16Oidentical12C+α system. As well as the known +ve and -ve parity bands many new levels are predicted and compared with experiment. The agreement between theory and experiment is very good both for the excitation energies and the decay properties. We predict the positions of two low-spin non-natural parity levels with Esub(x)<20 MeV and the positions of many high-spin states. In particular, we explain why the 8+ level seen in α-transfer at 22.5 MeV could not be found in the α-scattering cross sections and predict a second 8+ at 24.4 MeV. We discuss how the levels may be regarded as members of rotational bands and determine the terminating J-values for these bands. Finally we show that the usual rotational model would be a poor approximation for the cluster bands of 16O. (orig.)