Temperature and pressure induced Raman studies of C 60 oxide

We present temperature, laser power, and pressure dependent Raman spectral analysis of C 60 oxide (C 60O) thin films prepared by the photolysis method. The first order temperature, laser power, and pressure coefficients of the Raman frequencies are evaluated and are utilized for evaluating the thermal conductivity of C 60O. Its thermal conductivity is found to be 0.7 W m - 1 K - 1 which is marginally higher than that of bulk C 60. Raman frequencies corresponding to C-O and C-C bonds blueshift with a decrease in temperature which is attributed to the thermal contraction of C 60O molecules. The density functional measurements have been performed to optimize C 60O structure. The contraction in the C-O bond length has been corroborated with the experimental Raman shifts at different temperatures and is used to evaluate the linear expansion coefficient of C 60O. Pressure induced compression and polymerization of C 60O clusters are also illustrated. This study highlights the interplay between thermal and mechanical transformations in the C 60O cluster which may regulate its thermoelectric properties by tuning the intermolecular interactions.