Raman and infrared studies of single-crystal C₆₀and derivatives

Abstract

The authors describe results of Raman and infrared studies of single crystals of pure C60, CS2 solvated C60 (C 60.1.5CS2) and of (BEDT-TTF)2C60 (BEDT-TTF is bisethylenedithio tetrathiafulvalene of ET). They have observed phonon shifts in the crystal surfaces using Raman scattering which they assign to diffusion of molecular oxygen into the crystals; the results indicate that the presence of molecular oxygen hinders rotation of C60 molecules in the crystals. The four T1u vibrational modes in the infrared spectrum of pure C60 show fine structure which they attribute to Fermi resonances. They show that C60 vibrations in C 60.1.5CS2 crystals are less anharmonic than in pure C 60 crystals.