Abstract: The abstraction reaction of H with (CH₃)₃SiH was investigated at the high levels of ab initio molecule orbital theory. The geometries were optimized at the MP2 level with 6-31G(d) basis set, and G2MP2 level was used for the final energy calculations. The theoretical analysis provides the conclusive evidence that the main process is the hydrogen abstraction from the Si-H bond, leading to the formation of H₂ and silyl radicals; the hydrogen abstraction from the C-H bond has a higher barrier and is difficult to react. The kinetics was calculated with canonical variational transition-state theory (CVT) over the temperature range 200-1 000 K, and the theoretical rate constants match well with the later experimental values.

Key words: Reaction mechanism, Variational transition state, Tunneling effect, Rate constant