Alpha-gamma angular correlation studies of the reactions Si28(α, α′γ1.77) and O16(α, α′γ6.13)

Abstract Alpha-gamma angular correlations have been measured between inelastically-scattered alpha particles and de-excitation gamma rays from the reactions Si 28 (α, α′γ 1.777 ) and O 16 (α, α′γ 6.13 ). All measurements were made in the reaction plane. The Si 28 reaction involves the excitation of a 2 + level; angular correlations were measured at 41 scattering angles for this case. A 3 − excitation is involved in the O 16 reaction; angular correlations were measured at 24 scattering angles for this case. In both cases the data are found to disagree with the predictions of the plane-wave Born approximation (PWBA) and the adiabatic approximation. The results of three distorted-wave Born approximation (DWBA) calculations for the Si 28 reaction are presented. One of these calculations is shown to provide a reasonably good explanation of the experimental data at forward scattering angles.