Absolute differential cross sections at angles ranging from 10° to 170° and at bombarding energies of 5.6, 5.8, 6.0, and 6.2 MeV have been measured for the reaction ${\mathrm{Be}}^9$+${\mathrm{Li}}^7$, leading to each of the following states: ground and 0.75-MeV states of ${\mathrm{C}}^{15}$; ground, 6.10, 6.58 with 6.72, 6.89 with 7.01, 7.34, and 8.32-MeV states of ${\mathrm{C}}^{14}$; ground, 3.09, and 3.68 with 3.85-MeV states of ${\mathrm{C}}^{13}$; ground, 0.95, 1.64, and 2.62 with 2.72-MeV states of ${\mathrm{B}}^{12}$. The yields of the ${\alpha }_0$ and ${\alpha }_2$ groups at 20° (lab) have been measured at 3.3 MeV and at eleven other energies ranging from 5.0 to 6.2 MeV. Absolute cross sections were obtained by comparison of the yields of reaction products to elastic Coulomb scattering. Comparison is made of the total cross-section values with the ($2J+1$) rule. The angular distributions for the $t_0$ and $t_1$ groups, at each of the bombarding energies, are compared with the predictions of a two-mode (pickup and heavy-particle stripping) direct-reaction process in the plane-wave approximation.

• Received 18 April 1969

DOI:https://doi.org/10.1103/PhysRev.186.999