SHOCK-TUBE STUDY OF THE REACTION OF SI ATOMS WITH SICL4

The reaction of Si atoms with SiCl<INF>4</INF> was studied behind refl ected shock waves at temperatures between 1530 and 1800 K and pressure s around 1.7 bar by applying atomic resonance absorption spectroscopy (ARAS) for time-resolved measurement of Si atoms. The thermal decompos ition of a few ppm Si<INF>2</INF>H<INF>6</INF> was used as source for Si-atoms. The presence of an excess of SiCl<INF>4</INF> causes a fast consumption of Si atoms, which follows a pseudo-first-order rate law. The rate coefficient for the reaction of Si atoms with SiCl<INF>4 </IN F>Si+SiCl<INF>4</INF> reversible arrow<SUP>k1</SUP> SiCl<INF>2</INF>+S iCl<INF>2 </INF>was determined to be: k<INF>1</INF> =4.0+/-0.2x10<SUP> 13</SUP> cm<SUP>3</SUP> mol<SUP>-1</SUP> s<SUP>-1 </SUP>with no observ able temperature dependence in the temperature range of the present st udy.