A spectroscopic investigation of hydrogenated Li doped fullerane

We investigated two samples of Li6C60Hx, with different crystal structures, by means of anelastic and infrared spectroscopy. In both compounds the elastic energy loss does not display the relaxation peak, which in pure fullerene was attributed to the rotations of the buckyballs between energetically nearly-equivalent positions. We suggest that the disappearance of the relaxation process is due to bonding between buckyballs. The optical density of both specimens show new phonon lines appearing in the mid-infrared range, which in the previous literature were found in polymerized fullerenes. The results obtained by means of both spectroscopies clearly indicate the presence of chemical bonding between C60 molecules in the Li6C60Hx, independently of their crystal structure.