Evidence is given to show that ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ behaves like a tetrahedral rotor with a level sequence $0^{+}$, $3^{-}$, $4^{+}$, $6^{+}$, $7^{-}$, $8^{+}$,.... The charge form factors for excited states can be predicted from the ground-state form factor and excellent agreement with experiment is obtained for the $3^{-}$ and $4^{+}$ states at 6.13 and 10.35 MeV, respectively. The elastic-scattering data are fitted using deformed rather than spherical $\alpha$ clusters.

• Received 9 January 1979

DOI:https://doi.org/10.1103/PhysRevLett.42.876