Gas effusion spectra for O2-intercalated C60 solids

The evolution of oxygen (O-2) intercalated in fullerene (C-60) solids has been studied by gas effusion spectra. The O-2 concentration in C-60 solids estimated from gas effusion spectra increases with exposure time and temperature. In the gas effusion spectra for samples with a high O-2 concentration, a new oxygen evolution peak around 200 degrees C is found in addition to the two evolution peaks around 80 degrees C and 150 degrees C observed in the spectra of samples with low O-2 concentration. In X-ray diffraction patterns of O-2-intercalated samples, a peak related to the intercalation of O-2 is found around the (111) reflection of the face-centred cubic structure. The lattice constant of samples with high O-2 concentration is expanded a little by annealing at 300 degrees C in vacuum. The intercalation and evolution of G(2) in C-60 solids are discussed. (C) 1997 Elsevier Science Ltd.