Theoretical Investigation on the Reactions of H with (CH₃)_4-nSiH_n (n = 1–4)

The abstractions of H with (CH₃)_4-nSiH_n (n = 1–4) have been investigated at high levels of ab initio molecule orbital theory. Geometries have been optimized at the MP-2 level with 6–31G(d) basis set, and G2MP2 level has been used for the final energy calculations. Theoretical analysis provided conclusive evidence that the main process occurring in each case is the abstraction of H from the SiH bond leading to the formation of the H₂ and silyl radicals; the abstraction of H from CH bond has higher barrier and is difficult to react in each case. The kinetics of the title reactions have been calculated with variational transition state theory over the temperature range 200–1000 K, and the theoretical rate constants match well with the experimental values.