The following reactions which show a new level in ${\mathrm{Li}}^7$ at the listed excitation energy have been studied using protons, deuterons, and alphas of energies 7.9, 14, and 31 Mev, respectively, from the MIT cyclotron:

In all cases the differential range spectra of the emitted groups were measured in aluminum absorbers using a gated triple proportional counter. In addition, a low energy group was found in the ${\mathrm{Be}}^9(d,\alpha )$ reaction which would correspond to a level in ${\mathrm{Li}}^7$ at 7.50±0.17 Mev. No corresponding group was observed in the inelastic scattering reactions. Possible explanations of this are given. Preliminary results on the ${\mathrm{Li}}^7\mathrm{}(d,t)\mathrm{}{\mathrm{Li}}^{6*}$ and the ${\mathrm{Li}}^6(p,p^{\prime }){\mathrm{Li}}^{6*}$ reactions indicate a level in ${\mathrm{Li}}^6$ at 2.15±0.2 Mev. There is also evidence for two levels in ${\mathrm{Li}}^8$ at excitation energies of 1.0±0.2 and 2.3±0.2 Mev from the ${\mathrm{Li}}^7\mathrm{}(d,p)\mathrm{}{\mathrm{Li}}^{8*}$ reaction.

• Received 25 January 1951

DOI:https://doi.org/10.1103/PhysRev.82.658