Gas phase study of silicon-C60 complexes:: Surface coating and polymerization

(C-60)(n)Si-m(+) cationic clusters are produced in a laser vaporization source by quenching the vapors from two independent C-60 and silicon targets. They are analyzed in the gas phase by abundance and photofragmentation time-of-flight mass spectroscopy. For complexes containing only one C-60 molecule, silicon is unlikely to wet the fullerene surface. Mass spectroscopic studies are rather in favor of a three-dimensional growth of silicon clusters weakly bound to C-60. For larger systems, one can distinguish two classes of silicon atoms: most of them group in the form of compact islands (or clusters) and some others are directly involved in the linkage of C-60 molecules. Particular geometric structures for the stable polymers (C60Si)(n-2)(C-60)(2)(+), (C60Si)(n-1)C-60(+), and (C60Si)(n)(+) are postulated. (C) 2000 American Institute of Physics. [S0021-9606(00)00418-9].