Occurrence and fragmentation of high-mass fullerenes

Extracts of graphitic soot are shown by electron attachment mass spectrometry to contain, in addition to the well-known fullerenes C₆₀ and C₇₀, smaller quantities of larger carbon clusters, up to C₂₀₀. A structure for one of the more abundant clusters, C₇₆, is proposed. The data show the conspicuous absence of particular clusters. The relative stabilities of C₆₀, C₇₀ and C₈₄ were investigated by charge exchange and collision activated dissociation experiments. All the fullerene ions showed remarkable stability to fragmentation. At the highest collision energies accessible, fragmentation of C²⁺₇₀ and C^-₇₀ produced a series of products from C₂ loss, including the conspicuous formation of C₆₀ ions.