TOWARD A MICROSCOPIC DESCRIPTION OF THE SUBCOULOMB 1 % + 12C RESONANCES

A properly antisymmetrized, SUs-coupled r2C + 12C cluster model basis is used with simplified 12C + 12C interactions of Q l Q type to investigate the question: Is a simple quasimolecular basis sufficient to account for the observed density of low-J carbon resonances? The phenomenon of the so-called quasimolecular resonances constitutes one of the oldest problems [I] in the interaction of heavy ions. Although much theoretical progress has been made and a vast amount of experimental data has been accumulated, we are far from a complete understanding of the resonances in the excitation functions of the 12C + 1 2C and similar heavy ion systems. A large number of theoretical studies of such resonances seem to confirm the usefulness of the quasimolecular picture. Yet, an interpretation of the gross structure of the 12C + 12C resonances eems to be possible without invoking the existence of molecular pockets in the potentials for the rela-tive motion of the two ions [2]. Hard evidence for the quasimolecular picture must thus be sought in the fine struc-ture of these resonances. The large number of closely spaced, narrow fine structure components are the distinctive feature of the 12C + 12C resonances, compared with the simpler fine structure of the 160 + l60 resonances, for example. This may be related to the nonspherical shape of the two 12C nuclei, or in the language of SU, symmetry, the much richer SU, structure of the 12C t 12C cluster model wave functions. The 12C + 12C sytem may thus furnish the strictest test of the molecular interpretation. In addition, the subcoulomb and Coulomb barrier regio