The spin-orbit part $V_{\overrightarrow{I}·\overrightarrow{\mathrm{L}}}$ of the $\alpha$-nucleus interaction is estimated on the basis of the nucleon-$\alpha$ spin-orbit potential. Here $\overrightarrow{I}$ is the spin of the target nucleus and $\overrightarrow{\mathrm{L}}$ is the orbital angular momentum of $\alpha$-nucleus relative motion. The calculation assumes that the target nucleus undergoes no virtual excitation during the collision and that core polarization effects are absent. Numerical results are obtained for the nuclei of ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$, and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$. The result for the two first cases is found to be an order of magnitude smaller than the phenomenological values of $V_{\overrightarrow{I}·\overrightarrow{\mathrm{L}}}$ quoted in the literature. For ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ the value of $V_{\overrightarrow{I}·\overrightarrow{\mathrm{L}}}$ is nearly 10 times larger than for ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, a result which depends on the fact that for the valence nucleon $j=l-\frac{1}{2}$ in the former case, and $j=l+\frac{1}{2}$ in the latter case. For ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ no phenomenological values of $V_{\overrightarrow{I}·\overrightarrow{\mathrm{L}}}$ appear to be known.

• Received 14 February 1972

DOI:https://doi.org/10.1103/PhysRevC.6.1212