Absolute rate constants for the reaction of silylene with hydrogen, silane, and disilane

Abstract

Absolute rate constants for the reaction of silylene with hydrogen, silane, and disilane have been determined from direct time resolved measurements of silylene removal at room temperature. Silylene was generated and detected using laser resonance absorption flash kinetic spectroscopy. The rate constants are pressure dependent, consistent with expectations for the insertion reactions typical of silylene. The pressure dependence of the overall rate constants has been determined from 1 to 100 Torr for reaction with hydrogen and silane and from 1 to 10 Torr for reaction with disilane. The results for reaction with hydrogen and silane have been successfully modeled using RRKM theory and high pressure bimolecular rate constants have been extracted. The rate constants determined in this work are significantly ( 10-104 times) faster than those calculated from literature values for the Arrhenius parameters. These findings require a significant upward revision in the heat of formation of silylene, and may require modification of chemical vapor deposition mechanism in which silylene is invoked as a film growth precursor. © 1988 American Institute of Physics.