An exact-finite-range coupled-channels Born-approximation analysis, which takes into account multistep processes, was made of the reaction ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ ($0^{+}$, $2^{+}$, $4^{+}$). Good fits to data were obtained not only for the $0^{+}$ and $2^{+}$ state cross sections, but also for the $4^{+}$ state which is forbidden in a one-step process. Deviation of the distorted-wave Born-approximation result from the coupled-channel Born-approximation result was observed even for the allowed transition to the $0^{+}$ and $2^{+}$ states.

NUCLEAR REACTIONS ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$), $E=68\mathrm{}$ MeV calculated $\sigma \left(\theta \right)$ with CCBA and DWBA.

• Received 9 June 1975

DOI:https://doi.org/10.1103/PhysRevC.13.2579