Extreme [FORMULA] -clustering in the 18O nucleus

The structure of the 18 O nucleus at excitation energies above the [FORMULA] decay threshold was studied using 14 C + [FORMULA] resonance elastic scattering. A number of states with large [FORMULA] reduced widths have been observed, indicating that the [FORMULA] -cluster degree of freedom plays an important role in this N[FORMULA]Z nucleus. A 0 + state with an [FORMULA] reduced width exceeding the single-particle limit was identified at an excitation energy of 9.9±0.3 MeV. We discuss evidence that states of this kind are common in light nuclei and give possible explanations of this feature.