A prominent and wide resonance centered at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=32.5\mathrm{}$ MeV has recently been found in the ${(0\mathrm{}}_2^{+}{,0\mathrm{}}_2^{+})$ inelastic channel of the ${}^{12}$C${+}^{12}$C reaction. It has been suggested that it corresponds to a 6$\alpha$-particle-chain state in ${}^{24}$Mg. In the present work we study ${}^{12}$C${+}^{12}$C excitation functions between center-of-mass energies of 30 and 35 MeV in steps of 250 keV for weakly populated outgoing channels. We present the inelastic channels to the states above the $\alpha$-particle decay threshold, ${(0\mathrm{}}_1^{+}{,0\mathrm{}}_2^{+})$, ${(0\mathrm{}}_1^{+}{,3\mathrm{}}_1^{-})$, and ${(0\mathrm{}}_1^{+}{,4\mathrm{}}_1^{+})$, and the one- and two-nucleon transfer channels. In the inelastic and the transfer channels we observe correlated intermediate-width structures at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=31\mathrm{}$, 32.5, and 33.5 MeV, whose widths are appreciably smaller than the width measured in the ${(0\mathrm{}}_2^{+}{,0\mathrm{}}_2^{+})$ channel. Our $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=32.5\mathrm{}$ MeV angular distribution of the ${(0\mathrm{}}_1^{+}{,0\mathrm{}}_2^{+})$ channel exhibits oscillatory behavior and, unlike that of the ${(0\mathrm{}}_2^{+}{,0\mathrm{}}_2^{+})$ channel, does not display enhancement around ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=90\mathrm{}°$. Data were collected via the kinematic coincidence technique. For data reduction we use a novel approach allowing for the extraction of results on nonbinary channels.

• Received 16 October 1996

DOI:https://doi.org/10.1103/PhysRevC.55.1312