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Abstract

A series of experiments were performed to study the formation of MgC₆₀⁺ complexes via Mg⁺+C₆₀ collisions, and to study the structure and stability of the resulting complexes via optical spectroscopy and mass spectrometry. Collision experiments were carried out in a linear ion trap apparatus under conditions of controlled collision energies, reactant densities, and buffer gas pressure. Ion trap mass spectrometry was used to measure the relative reaction rates for complex formation, charge transfer, and fragmentation reactions in Mg⁺+C₆₀ collisions. Laser-induced photodissociation was then used to study the MgC₆₀⁺ complexes in order to measure their stability and identify their molecular structure. Absolute photodissociation cross sections were determined for complexes generated at low collision energies and reactant densities over the wavelength range of 1300-280 nm and were in the range from 2x10^-20 cm² to 5x10^-17 cm² in magnitude. The shape of the generated cross-section curve indicates that at low collision energies most of these complexes are exohedrals. More refined measurements of samples generated at optimum buffer gas pressures and higher collision energies demonstrated the existence of a second more slowly dissociating fraction that apparently results from the presence of endohedral complexes. (C) 2002 American Institute of Physics.