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The 12C(16O,12C 12C)α reaction has been measured at Ebeam=75 MeV, for 24Mg emission from 0 to 180 degrees. This energy coincides with an enhancement observed in earlier measurements of the 12C+16O system. The properties of the angular correlations of the reaction products are found to be consistent with a resonance in 28Si at Ex=48.9 MeV, with spin J=17±1. The decay properties of the states in 24Mg, populated following α-decay of the resonance, suggest that the state in 28Si possesses a triaxial structure linked to a (sd)8(fp)4 configuration.

A study has been made of the 12C(16O,12C12C) α reaction between the centre of mass energies of 28.3 to 36.8 MeV. A number of resonances in 28Si have been observed for final channels leading to the unbound 10.35, 11.09 and 14.82 MeV states in 16O. At two energies associated with previously observed resonances, the angular correlations of the exit channel particles have been analysed to measure the dominant angular momentum of the 28Si compound nucleus. Additional data were acquired at two off-resonance energies for comparison. Using an essentially model independent analysis, the values obtained were all in the region of 19–21 h , and are comparable with the grazing angular momentum in the entrance channel. The results are relevant to recent theoretical predictions of planar α-cluster structures in 28Si and are discussed in the context of the model predictions.