The $\alpha$-particle cluster structure of ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$, which is of considerable interest for investigation of the persistence of $\alpha$ clustering in the region of the $\mathrm{sd}$-shell closure, is studied within the frame of a local-potential approach. It is shown that the model leads to specific predictions if continuity with existing unique $\alpha +{}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ optical potentials ïs insisted upon; in particular, the existence of an as yet experimentally unknown $\alpha$-cluster negative-parity band, starting just above the $\alpha +{}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ threshold, is strongly suggested.

• Received 27 March 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.1215