Low energy modes of metals in fullerene cages

Vibrations between carbon cage and Sc are discussed in the endohedral compound Sc2@C84. The attention was concentrated to the region below 300 cm-1 in which one expects this type of motions. Comparing Raman and far-infrared spectra for empty and filled cages with the same symmetry we identified 9 modes for the Sc-cage vibrations. This large number of the modes will be discussed from a point of view of different mechanisms of splitting. We present also temperature dependent measurements which suggest a possible order-disorder phase transition between 160 and 180K.

Keywords:

• endohedral
• metallofullerenes
• Raman
• infrared