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Theoretical study of the pyrolysis of methyltrichlorosilane in the gas phase. 1. Thermodynamics.

Ge Y, Gordon MS, Battaglia F, Fox RO

Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA. mark@si.fi.ameslab.gov

Structures and energies of the gas-phase species produced during and after the various unimolecular decomposition reactions of methyltrichlorosilane (MTS) with the presence of H2 carrier gas were determined using second-order perturbation theory (MP2). Single point energies were obtained using singles + doubles coupled cluster theory, augmented by perturbative triples, CCSD(T). Partition functions were obtained using the harmonic oscillator-rigid rotor approximation. A 114-reaction mechanism is proposed to account for the gas-phase chemistry of MTS decompositions. Reaction enthalpies, entropies, and Gibbs free energies for these reactions were obtained at 11 temperatures ranging from 0 to 2000 K including room temperature and typical chemical vapor deposition (CVD) temperatures. Calculated and experimental thermodynamic properties such as heat capacities and entropies of various species and reaction enthalpies are compared, and theory is found to provide good agreement with experiment.

Published 22 February 2007 in J Phys Chem A Dyn Kinet Environ Chem Spectrosc Struct Theory, 111(8): 1462-74.
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