High-resolution total reaction excitation functions for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+ ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and detailed angular distributions for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},\alpha ){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ have been measured. The interplay between (fifteen) resonance amplitudes and $l$-window (background) amplitudes is emphasized. Spin assignments, obtained from the ${\alpha }_0$ data, are dominated by values of $8\hslash$ and $9\hslash$ while the grazing partial wave varies from $l=5\mathrm{}$ to $l=10\mathrm{}$ over the energy range studied. Elastic widths for the low-energy resonances indicate a dinuclear molecular nature; higher-energy resonances appear to originate from a more complex nuclear configuration.

• Received 31 May 1983

DOI:https://doi.org/10.1103/PhysRevLett.51.881