The $E2\mathrm{}$ and $M1\mathrm{}$ components of the ${}^{16}\mathrm{O}(p,\gamma {)}^{17}\mathrm{F}$ and ${}^7\mathrm{Be}(p,\gamma {)}^8\mathrm{B}$ cross sections, which are involved in the analysis of Coulomb breakup data, are studied in a microscopic model. These investigations provide examples of unusual S factor low-energy dependences.

• Received 11 March 1999

DOI:https://doi.org/10.1103/PhysRevC.60.015803