Dual-level direct dynamics studies on the reactions of OH radicals with SiH3CH3 and SiH4

The multiple-channel reaction SiH3CH3 + OH → products (R1) and the single-channel reaction SiH4 + OH → SiH3 + H2O (R2) have been studied by the direct dynamics method at the QCISD(T)/6-311++G(3df,3pd)//BH&H-LYP/6-311G(d,p) level. The rate constants for those reactions are calculated by improved canonical variational transition state theory (ICVT) with small-curvature tunneling (SCT) contributions in a temperature range 200–3000 K. For reaction (R1), H-abstraction from the SiH3 group is the major channel. Since methyl substitution increases the reactivity of Si–H bond in silane, the rate constants of (R1) are larger than those of (R2) over the whole temperature region.