We have evaluated the cross section for electroexcitation of giant resonance states in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, using the model due to Kamimura, Ikeda, and Arima (a particle-hole model with selected two-particle-two-hole components describing surface oscillations superimposed on the giant resonance). The model seems capable of providing much of the fine structure observed in the recent Saskatchewan electron scattering experiments. The $T=1,1^{-}$ isospin and $1^{-}$ and $2^{-}$ spin-isospin collective states again play a dominant role, as in the previous Brown-Gillet model (with whose predictions our results are compared), but surface-vibration satellites and other smaller states add some amount of fine structure. We have also evaluated widths by the reduced-widths formalism.

• Received 26 April 1968

DOI:https://doi.org/10.1103/PhysRev.175.1235