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Unimolecular decomposition of SiH sub 4 , SiH sub 3 F, and SiH sub 2 F sub 2 at high temperatures

Journal Article · · Journal of Physical Chemistry; (United States)
DOI:https://doi.org/10.1021/j100156a035· OSTI ID:5169686

The thermal decomposition of SiH{sub 4}, SiH{sub 3}F, and SiH{sub 2}F{sub 2} diluted in Ar was studied behind incident shock waves by monitoring IR emission from these reactant molecules. The rate constants of the unimolecular decomposition for all of three molecules were found to be in the pressure falloff region over the present experimental conditions (T = 1,190-2,150 K and P = 0.2-1.6 atm). The activation energies of measured rate constants were compared with heats of reactions for the various possible pathways for the thermal decomposition of these molecules and its was concluded that three-center H{sub 2} elimination reactions were the dominant pathways for unimolecular reactions of SiH{sub 4-n}F{sub n} (n = 0, 1, and 2). These rate constants decrease with increasing number of fluorine atoms, n, in SiH{sub 4-n}F{sub n}. RRKM falloff calculations have been performed to examine the effect of fluorine substitution on the unimolecular decomposition rates of these molecules.

OSTI ID:
5169686
Journal Information:
Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:3; ISSN 0022-3654; ISSN JPCHA
Country of Publication:
United States
Language:
English