Investigation of deformation effects on the decay properties of 12C+α Cluster states in 16O

We have analyzed the elastic scattering angular distributions data of the α+12C reaction over a wide energy range (Elab=28.2 to 35.5 MeV) within the framework of the Optical Model formalism. A double folding (DF) type real potential was used with a phenomenological Woods–Saxon-squared (WS2) type imaginary potential. Good agreement between the calculations and experimental data was obtained. By using the real DF potential we have calculated the properties of the α-cluster states in 16O by using the Gamow code as well as the α-decay widths by using the WKB method. We implemented a 12C+α cluster framework for the calculation of the excitation energies and decay widths of 16O as a function of the orientation of the planar 12C nucleus with respect to the α-particle. These calculations showed strong sensitivity of the widths and excitation energies to the orientation. Branching ratios were also calculated and though less sensitive to the 12C orientation, it was found that 12Cgs+α structure, with the α-particle orbiting the 12C in its ground state, is dominant. This work demonstrates that deformation, and the orientation, of 12C plays a crucial role in the understanding of the nature of the α-cluster states in 16O.