FT-RAMAN SPECTROSCOPIC STUDIES OF C-60 AND C-70 SUBSEQUENT TO CHROMATOGRAPHIC-SEPARATION INCLUDING SOLVENT EFFECTS

C-60/C-70 containing soot was produced by are-vaporization of graphite. The chromatographic separation of soot yielded fairly pure C-60 and C-70 samples. High-resolution FT-Raman spectra of C-60 and C-70 specimen as well as C-60 and C-70 solutions including polarization measurements are recorded. Compared to the spectrum of solid C-60, some Raman bands of the C-60 solution change their position and shape. Even the purest commercial C-60 samples contain solvent inclusions (impurities) in the order of some percentage. The chromatographic separation combined with Raman polarization measurements of solutions allows an evaluation of the fundamental vibrations of the C-60 molecule. Its assignment, in accordance with the group theoretical expectation, is proposed. The existence of small amounts of C-60 isomers (symmetry, e.g., C-2v, D-2h, D-2d) in icosahedral C-60 (I-h) is affirmed based on the polarization measurements. For C-70 the most extended set of Raman frequencies is presented.