Raman and infrared determination of vibrational fundamentals of single-crystal C₆₀and derivatives and of C₇₀

Abstract

We describe results of Raman and infrared (IR) studies of single crystals of pure C60, CS2 solvated C60 (C601.5CS2), (BEDT-TTF)2 C60 (BEDT-TTF or ET is bis(ethylenedithio)tetrathiafulvalene) and C70. We find that changing the crystalline environment of C60 has little effect upon the vibrational frequencies of the intramolecular vibrations but has some effect on relative intensities of peaks. By comparing our IR and Raman spectra using the published inelastic neutron scattering and surface enhanced Raman data we have been able to identify the complete set of 46 fundamental intramolecular vibrational frequencies of C60 and 64 of the 122 fundamentals of C70. Theoretical calculations for C60 are not accurate enough to completely assign the symmetries of the identified fundamentals. We comment on effects of oxygen and laser power on the Raman spectrum of C60.