12C+12C Molecule-Like State in the Sub-Coulomb Barrier Region of 24Mg

The 12C+12C molecule-like states in the sub-Coulomb barrier region are investigated using the semi-microscopic 12C+12C cluster model. It is discussed that the 12C+12C molecule-like states have not only large carbon width but also large E2 decay width to the ground state of 24Mg. Resonances in the sub-Coulomb barrier region of the 12C+12C system have first been observed as heavy-ion resonance phenomena.l) However, we have not yet the complete understanding of the resonance mechanism and the nuclear structure in this system. The Nogami-Imanishi model (N-I mode1)2),3) is the first successful model that gives an interpretation of the resonance mechanism from a viewpoint of the nuclear molecular structure. The N-I model for the 12C + 12C system with the 2+ intrinsic excitation (4.44 MeV) of one 12C nucleus has been shown to reproduce the three prominent resonances first observed just below the Coulomb barrier.3) This model, however, could not explain many resonances observed in later experiments.4) For this defect, Kondo, Matsuse and Abe5) have proposed an extended model of the N-I model, where the 2+ state of both 12C nuclei is excited during collision and strongl