Scarcity of States of ${\mathrm{Li}}^7$, from Magnetic Observation of ${\mathrm{Be}}^9(d,\alpha ){\mathrm{Li}}^7$

The alpha-spectrum of the reaction ${\mathrm{Be}}^9(d,\alpha ){\mathrm{Li}}^7$ is observed at a bombarding energy 600 kev. Above the well-known 480-kev excited state of ${\mathrm{Li}}^7$ there is no further excited state, having a transition as much as 5 percent as intense as the ground-state transition, in the range of excitation energies up to 2.5 Mev and from there, where the ($d,2\mathrm{}\alpha$) reaction begins to obscure the observations, up to 3.6 Mev there is no sharp line more than 10 percent as intense as the ground-state line. The observations are made with a magnetic heavy-particle spectrograph giving an extended spectrum with a second-order focus on a photographic plate.