Extreme \( \alpha\) -clustering in the 18O nucleus

The structure of the 18O nucleus at excitation energies above the \( \alpha\) decay threshold was studied using 14C + \( \alpha\) resonance elastic scattering. A number of states with large \( \alpha\) reduced widths have been observed, indicating that the \( \alpha\) -cluster degree of freedom plays an important role in this N \( \ne\) Z nucleus. A 0+ state with an \( \alpha\) 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.