Binary clusters SinCm are produced in a laser vaporization source from
SixC1-x mixed targets. Different composition regimes are investigated
by abundance and photoinduced dissociation mass spectroscopy. In the
case of stoichiometric silicon-carbide clusters (x = 0.5), no clear ma
gic size is detected but rather the marked effects of a lower binding
energy of silicon as compared to carbon atoms. The structural changes
induced by the presence of foreign atoms are discussed in the case of
carbon-rich clusters (x << 1) for which the formation of heterofullere
nes is observed. (C) 1997 Elsevier Science B.V.