Dehydrogenation of gaseous hydrogen-containing molecules: The formation of elemental and molecular clusters

A general concept employing the dehydrogenation of hydrogen-containing organic and inorganic compounds is shown to readily affect the production of a wide variety of elemental and binary clusters. Hydrogen-containing molecules such as ${\mathrm{C}}_2$ ${\mathrm{H}}_4$, ${\mathrm{NH}}_3$, ${\mathrm{SiH}}_4$, ${\mathrm{H}}_2$S, or ${\mathrm{H}}_2$O, are introduced into an extremely energetic plasma generated from laser irradiation of a metal surface; this plasma dehydrogenates the molecules to produce nascent C, N, Si, S, and O atoms. These C, N, Si, S, and O atoms can react with metal atoms or ions contained in the plasma and form metallocarbohedrenes or metal-carbide, metal-nitride, metal-silicide, metal-sulfide, or metal-oxide clusters. Alternatively, individual constituents may associate to produce pure elemental clusters such as those comprised of carbon or silicon. In principle, this technique can be applied to all gaseous hydrogen-containing compounds. The results of the present study provide an alternative way (in some cases it could be the only feasible way) to generate clusters of these materials. Study of the ensuing distributions provides unique insight into the cluster-formation mechanisms involving this type of cluster source.