Estimation of the Arrhenius parameters for SiH sub 4 l reversible SiH sub 2 + H sub 2 and. Delta. H sub f degree (SiH sub 2 ) by a nonlinear regression analysis of the forward and reverse reaction rate data
- Sandia National Labs., Albuquerque, NM (USA)
- Univ. of Minnesota, Minneapolis (USA)
The authors have extended a calculational procedure for the estimation of Arrhenius parameters for unimolecular reactions by direct regression of RRKM-derived predictions of experimental data to include nonlinear regression of experimental data for the reverse reaction. Both the forward and reverse reaction experimental data may then be used to access the validity of kinetic parameters assumed in the RKM model. Using recent direct measurements of the rate of SiH{sub 2} insertion into H{sub 2}, a recent SiH{sub 4} pyrolysis study in a static reactor, and earlier shock tube and static reactor SiH{sub 4} pyrolysis studies, estimates for the high-pressure Arrhenius parameters for the SiH{sub 4} decomposition reaction are obtained. The RRKM model is a good representation of the data over a 900 K temperature range, at pressures from 1 to 4,000 Torr. The 1,100 K Arrhenius expression is: log k(T) (s{sup {minus}1}) = (15.79 {plus minus} 0.5) {minus} (59.99 {plus minus} 2.0) kcal mol{sup {minus}1}/2.3 RT. The use of a correction factor to the density of states due to the effects of anharmonicity is seen to lead to improvement in the agreement with the data. The large uncertainty in the preexponential was due to the existence of a range of permissible A factors which provided adequate fits.
- OSTI ID:
- 5926092
- Journal Information:
- Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:1; ISSN 0022-3654; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ARRHENIUS EQUATION
CHEMICAL REACTION KINETICS
DATA
DISSOCIATION HEAT
ENTHALPY
EQUATIONS
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
MATHEMATICS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
REACTION KINETICS
REGRESSION ANALYSIS
SILANES
SILICON COMPOUNDS
STATISTICS
THEORETICAL DATA
THERMAL DEGRADATION
THERMODYNAMIC PROPERTIES