0⁺(GS)→2⁺(4.44 MeV) transition density in ¹²C

A model is proposed for the 2⁺ first excited state in ¹²C in which the dominant configurations outside the p shell are assumed to come from mixing with an 'idealised' isoscalar giant quadrupole resonance. A small admixture of this resonance is capable of reproducing the high collectivity of the first excited state and gives a reasonably good fit to inelastic electron scattering data. The model gives a possible explanation of the lack of energy-weighted E2 strength up to about 30 MeV in this nucleus, and a simple extension of the model gives an overall improvement in theoretical estimates of experimental quadrupole moments in the ¹²C region. The folding model is used to discuss the properties of the corresponding transition and reorientation potentials for coupled-channels calculations of ¹²C+¹²C scattering.