Theoretical study on the reaction of SiH(CH₃)₃ with SiH₃ radical

The multiple-channel reactions SiH₃ + SiH(CH₃) ₃ -→ products are investigated by direct dynamics method. The minimum energy path (MEP) is calculated at the MP2/6-31+G(d,p) level, and energetic information is further refined by the MC-QCISD (single-point) method. The rate constants for individual reaction channels are calculated by the improved canonical variational transition state theory with small-curvature tunneling correction over the temperature range of 200-2400 K. The theoretical three-parameter expression k(T) = 2.44 × 10^-23 T^3.94 exp(-4309.55/T) cm³/(molecule s) is given, Our calculations indicate that hydrogen abstraction channel R1 from SiH group is the major channel because of the smaller barrier height among five channels considered.