A study is made of the energy levels of ${\mathrm{Be}}^9$ with particular emphasis on comparing the inelastic scattering data with the shell-model predictions. The differential cross sections for inelastic scattering of alpha particles are calculated in distorted-wave Born approximation using a central spin-independent potential to represent the interaction between the incident alpha and each target nucleon. The target wave functions are taken to be intermediate-coupling shell-model wave function. The agreement between theory and experiment is excellent for values of the intermediate coupling parameter, $\frac{a}{K}$, which best reproduce the level spectra. The results favor a value $\frac{a}{K}=2.86\mathrm{}$ over the other popular value, $\frac{a}{K}=1.4\mathrm{}$. It is suggested that the 1.7-and 11.3-Mev levels do not arise from the ${\mathrm{}\left(1p\right)\mathrm{}}^5$ configuration.

• Received 27 March 1959

DOI:https://doi.org/10.1103/PhysRev.115.963