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The purpose of this account is to describe some of the key, early mass spectrometric studies of gas-phase carbon clusters, which served as a prelude to the Huffman-Kratschmer discovery as well as some of the more recent investigations of fullerene properties in the gas phase. The authors concentrate on analytical investigations of fullerene structure and chemistry as studied by mass spectrometry.

The formation of endohedral C 60 He + complexes in mass spectrometric experiments in which C 60 + collides with He at kiloelectronvolt energia has been modeled with molecular dynamics simulations. Experimental results have shown that the collision energy at which the greatest abundance of C 60 He + is observed is 5000 eV, while molecular dynamics simulations predict that optimal complex formation should occur in 8000-eV collisions

Negative ion/description chemical ionization mass spectrometry was used in this paper to characterize La{sub x}@C{sub n} and Y{sub x}@C{sub n} fullerenes in soot generated from metal compound-impregnated graphite rods. La@C{sub 82} and La@C{sub 80} are extracted by pyridine from the soot, but La@C{sub 60} and La@C{sub 70} are not. There are greater abundances of metallofullerenes with the lower ionization potential metal atom in the pyridine extracts. These observations indicate that metallofullerenes exist as ionic complexes with fullerenes (La{sub x}@C{sub n}){sup +}C{sub n}{sup -}. 16 refs., 4 figs.

The availability of macroscopic quantities of fullerenes has resulted in a vast number of physical and chemical studies of these new materials. However, the mechanisms that lead to the formation of these spherical carbon allotropes are not well understood. Mass spectral evidence has been obtained for the size-selective growth of fullerenes through the coalescence of cyclo[n] carbons, molecular carbon allotropes consisting of monocyclic rings with n carbon atoms. Whereas coalescence of cyclo[30]carbon (cyclo-C30) produces predominantly buckminsterfullerene (C60), the smaller rings cyclo-Cl8 and cyclo-C24 preferentially produce fullerene C70 through distinct intermediates. The present studies not only provide new insights into fullerene formation mechanisms but also raise the possibility of tailoring the size distributions of fullerenes by variation of the appropriate properties of the precursors.

High-energy (kilovolt) collisions of carbon cluster (fullerene) cations with helium are used to differentiate between species that do and do not satisfy the isolated pentagon rule (IPR). The initial studies of collisions of C 60 .+ and C 70 .+ with helium, which showed incorporation of the helium atom in the fullerene cage and inelastic scattering, have been extended to other C x + with even x