Electronic and chemical properties of small silicon clusters in reactions with silane.

The microscopic surfaces of small silicon clusters offer a model for studying chemistry at highly reactive silicon centers. Positively and negatively charged clusters containing 2-7 atoms are prepared by laser evaporation of a solid silicon target located outside of the ion cell of a Fourier transform mass spectrometer. The trapped clusters bimolecularly react with SiD sub 4 at room temperature primarily by addition of SiD sub 2 accompanied by loss of D sub 2. Sequential reactions of bare silicon cluster cations and SiD sub 3 sup (+) to form still larger deuterated Si sub x D sub y sup (+) species are also observed.