A number of states in ${\mathrm{Si}}^{28}$, ${\mathrm{Mg}}^{26}$, and ${\mathrm{Mg}}^{24}$ have been studied using the ($\alpha , {\alpha }^{\prime }\gamma$) reaction and the angular correlation method-II geometry of Litherland and Ferguson. In ${\mathrm{Si}}^{28}$, spin and parity assignments of 1, ($6^{+}$), and $1^{-}$ are made to the 7.38-, 8.51-, and 8.94-MeV states, respectively. The 4.90-MeV state in ${\mathrm{Mg}}^{26}$ is assigned $J^{\pi }=4^{+}$. Earlier $J^{\pi }$ assignments to the $3^{-}$ 6.88-, $2^{+}$ 7.41-, and $2^{+}$ 7.93-MeV states in ${\mathrm{Si}}^{28}$, and the $1^{-}$ 8.44-, $2^{+}$ 9.00-, and $1^{-}$ 9.15-MeV states in ${\mathrm{Mg}}^{24}$ are confirmed, as is an earlier value of the multipolarity mixing ratio of the 2.94→1.81 $\gamma$-ray transition in ${\mathrm{Mg}}^{26}$.

• Received 14 March 1969

DOI:https://doi.org/10.1103/PhysRev.187.1369