Infrared absorption of polarons in C60.

Abstract

We consider infrared absorption in charged and photoexcited ${\mathrm{C}}_{60}$ using a Su-Schrieffer-Heeger model supplemented by a force field model to treat molecular vibrations. Intensities are calculated assuming the principal cause of absorption is the charged phonon effect. Our calculated frequencies for ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{60}^{\mathrm{\ensuremath{-}}6}$ are in good agreement with experiment but the calculated intensities are at best in qualitative agreement. For photoexcited ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{60}^{\mathrm{\ensuremath{-}}}$ the calculations indicate a number of additional infrared peaks which are in principle accessible to experiment.