Angular distributions have been measured for angles ${\theta }_{\mathrm{lab}}\ge 4°$ for (${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$) transitions on $2s-1d$ and $1f-2p$ shell targets at bombarding energies $36\le E_{\mathrm{lab}}\le 53$ MeV. More than one transition has been studied for each $l$ value from 1 through 4 and the transition $Q$ values vary from nearly optimum to severely unfavored. A full-finite-range distorted-wave Born approximation analysis is successful in reproducing angular distribution shapes for transitions with bombarding energies well above the entrance channel Coulomb barrier, but such an analysis fails badly to fit angular distributions for lower bombarding energies, especially for unfavored $Q$ value transitions. There is some variation of the extracted absolute spectroscopic factors with bombarding energy, but in general the spectroscopic factors are in good agreement with (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$) results if the distorted-wave Born approximation predictions are normalized to the experimental cross sections at the grazing angle. The relative cross section contributions to the full distorted-wave Born approximation calculation from different $m$ substates are strongly dependent on $Q$ value and on small changes in optical potential parameters; the failures in the distorted-wave Born approximation analysis may arise from a miscalculation of the nuclear alignment.

NUCLEAR REACTIONS ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{48,50}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ni}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N})$; measured $\sigma (E,\theta )$; DWBA analysis; enriched targets; $36 \mathrm{MeV}\le E\le 53 \mathrm{MeV}$.

• Received 18 June 1976

DOI:https://doi.org/10.1103/PhysRevC.14.2174