Diamond from fullerenes: Evidence from Raman measurements

We present the Raman characterization of transformed fullerene samples obtained by applying high (∼20 GPa) nonhydrostatic pressures on ${\mathrm{C}}_{60}$ or ${\mathrm{C}}_{60}$-${\mathrm{C}}_{70}$ powders. Only two clear features are observed. The first is a peak at 1330 ${\mathrm{cm}}^{\mathrm{-}1}$, signature of the existence of cubic diamond. The second is a broadband of unknown origin centered at approximately 1450 ${\mathrm{cm}}^{\mathrm{-}1}$. These results confirm previous crystallographic analysis that showed that our samples consist of polycrystalline diamond embedded in an amorphous matrix.