Optical properties of the vibrations in charged C60 molecules.

The transition strengths for the four infrared-active vibrations of charged C60 molecules are evaluated in self-consistent density functional theory using the local density approximation. The oscillator strengths for the second and fourth modes are strongly enhanced relative to the neutral C60 molecule, in good agreement with the experimental observation of “giant resonances” for those two modes. Previous theory, based on a “charged phonon” model, predicted a quadratic dependence of the oscillator strength on doping, but this is not borne out in our calculations. Typeset using REVTEX 1