Effect of α-nucleus potential on the ²⁸Si(α,d)³⁰P reaction

Microscopic and macroscopic distorted wave Born approximation calculations have been performed using molecular, Michel and normal optical potentials to analyze the angular distributions of cross sections for 12 transitions populating the 0.0, 0.709, 1.454, 1.974, 2.538, 2.72, 2.84, 3.02, 3.93. 4.62, 5.42, and 7.20 MeV states of ³⁰P via the (α,d) reaction. Only the molecular potential is able to produce satisfactory fits to the data, but the normal optical potential is found to be inadequate in accounting for the large-angle data and the Michel potential is just unsatisfactory. The spectroscopic factors for the d-cluster transfer are deduced from the full finite-range distorted-wave Born approximation and compared to the shell-model predictions for the even-parity states.The spin-parity assignment of the 3.93 MeV state is confirmed. The best-fit value for the finite-range parameter for the zero-range DWBA calculations is also deduced.