Theoretical cross sections in the ¹²C(α,γ)¹⁶O reaction

The ¹²C(α,γ)¹⁶O reaction seems to be explained by the simple reaction mechanism of the direct-capture potential model. The theoretical cross section at E_c.m. = 0.3 MeV is found to be enhanced with the E2 transition. This is caused by the tail of the subthreshold $2_1^{+}$ state (E_x = 6.92 MeV). The total S-factor is consistent with the previous studies. The photodisintegration of ¹⁶O is also found to be dominated by the E2 excitation in the vicinity of the α-particle threshold. (paper)