INSERTION REACTIONS OF MONOVALENT SILICON - A NONVANISHING BARRIER FOR THE SILYLIDYNE PLUS HYDROGEN REACTION SIH+H-2

Ab initio quantum mechanical methods have been applied to the SiH (X 2PI) insertion into the H-2 molecule. The transition state has no elements of symmetry. The classical barrier height is predicted to be 5.6 +/- 1 kcal/mol. The barrier is qualitatively consistent with an estimate from Jasinski's experimental reaction rates, which are much slower than those observed for the related CH + H-2, SiH + SiH4, and SiH2 + H-2 reactions.