Surface oxidation of donor heteroatoms in crystalline fullerene-donor compounds

The studies of X-ray photoelectron spectra of a series of crystalline fullerene molecular complexes, (D)x·(F)·(R)y, showed that in addition to the main state of a heteroatom of donor, there are heteroatoms in higher oxidation states on a crystal surface. The causes for donor oxidation and the appearance of heteroatoms in higher oxidation states are discussed.