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The superconductivity has been detected in the Sn-doped C60 samples by AC susceptibility measurements. The Sn-doped C60 sample is insensitive to air. EDS and XRD examinations show that the Sn-atoms have intercalated into the interstitial positions of the C60 lattice during a very slow diffusion reaction process.

The linearly polarized Cu L3-edge x-ray-absorption near-edge structure (XANES) of Bi2Sr2CaCu2O8 + delta has been measured and the spectra are interpreted by the full multiple-scattering approach in real space. The polarized spectra over a range of 20 eV can be predicted in terms of the one-electron dipole (DELTA-l = +1) transition Cu 2p --> epsilon-d, probing the unoccupied d-like (l = 2) density of states projected on the Cu site with orbital angular momentum m(l) = 0, 1 in the E parallel-to z spectra, and the m(l) = 2, 1, and 0 in the E perpendicular-to c spectra. The oscillator strength for the dipole allowed transitions (DELTA-l = -1) Cu 2p --> epsilon-s is shown to be a factor of 100 weaker than the 2p --> 3d transitions. The Coulomb interaction in the final state between the Cu 2p core hole and the excited Cu 3d electron is found to be 5.5 eV forming a bound state below the continuum threshold, the well-known Cu L3 white line. On the contrary, the core hole induces a nearly rigid redshift about 1 eV of the high-energy conduction bands.

A simple and inexpensive method for the purification of gram quantities of >99.5% pure C60 and > 98% pure C70 by a fractional crystallization process in carbon disulfide or o-xylene is described. This process is based on the finding that C60 was enriched in the solid deposit, whereas C70 was enriched in the mother liquor during crystallization of fullerenes due to differential solubilities of these two fullerenes, C60 and C70, in these solvents.