Differential cross sections for the ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$(${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$) reaction were measured at ${\theta }_L=10, 15, 20°$ for bombarding energies near 100 and 120 MeV. These data are consistent with direct ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ transfer to highly excited, high-spin states in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$. The energy spectra, angular distributions, level systematics of $\mathrm{sd}$-shell nuclei, and shell-model calculations strongly suggest that a state observed at 15.8 MeV is the previously unidentified $8^{+}$ member of the ground-state rotational band of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$.

NUCLEAR REACTIONS ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$(${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$), $E_{{}_{}{}^{12}{}_{}{}^{}\mathrm{C}}\simeq 100,120$ MeV; measured $\sigma$ for ${\theta }_{\mathrm{lab}}=10, 15, 20°$; deduced ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ levels. Comparison with shell-model calculations, suggested $8^{+}$ levels.

• Received 9 October 1979

DOI:https://doi.org/10.1103/PhysRevC.21.764