Strongly absorbing optical potentials in a distorted-wave context are unable to describe the single neutron-stripping and single proton-pickup reactions induced by 44 MeV ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ on a ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ target. Modifications of the imaginary potential consistent with the surface transparency requirements for backward angle ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ elastic scattering greatly improve the transfer predictions. In addition, the altered potentials yield a reasonably qualitative picture of the backward elastic excitation function over a broad range of energy.

NUCLEAR REACTIONS ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$), ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$), excitation function and angular distribution for elastic scattering.

• Received 21 June 1979

DOI:https://doi.org/10.1103/PhysRevC.20.2124