A Kinetical and Thermodynamical Theoretical Study On Reaction （¹A₁）SiH₂+H₂→SiH₄

In This paper, SCF ab intio method was used to treat the reactants, product and transition state of insertion reaction (¹A₁)SiH₂+H₂→ SiH₄. The configurations of each species were optimized with 3-21G basis set, and the vibrational frequencies for the configuration were calculated. Then the transition state entropy change ΔS^≠ and reaction rate constant kT was calculated with Eyring transition state theory. The negative ΔS^≠ means the reaction pass through a tight transition state. The rate constant value k(298K)=6.2357 × 10^-15lmol^-1s^-1 is in good agreement with the experimental result by Inoue k(298K)=(1.0 0.4) × 10^-16lmol^-1s^-1. Finally the enthalpy ΔH, free energy ΔG and the equilibrium constant K(T) of this reaction were calculated, and we point out that this reaction is exo-thermal and can go on spontaneously. We also corrected all above kinetic and thermodynamic quantities with frequency correction and zero-point energy correction. After correction the theoretical reaction rate constant k(298K)=3.9799 × 10^-17lmo1^-s^-1 is in better agreement with the experimental result than before.