C60+ defect centers: effect of rubidium intercalation into C60 studied by EPR

The vanishing of C60+ EPR centers during the intercalation of polycrystalline C60 with rubidium is described as a two-stage process with inter- and intragrain penetration of rubidium into the C60 sample. This process leads to quenching of C60+ hole states through a recombination process. Two aspects of the results are discussed: 1. EPR assignment of the spectrum usually observed in pristine polycrystalline C60 samples. 2. Similarity of the kinetics of alkali inter- and intragrain penetration into powdered C60 to the kinetics of oxygen penetration through C60 film, accompanied by the generation of C60+ centers.