The mechanism of the addition reaction of disilyne and hydrogen has been studied by using ab initio calculation of quantum chemistry and density functional theory. All of the structures of the stationary points on the reaction channels such as reactants, transition states and products have been optimized at B3LYP/6-311G** level; the vibration frequencies and zero-point vibration energy have been also calculated and analyzed to determine the reality of the transition states. The total energies of the matters were given by the method QCISD(T)/6-311G**//B3LYP/6-311G** and corrected with zero-point energies. The computa-tion indicated that the stable silicyl alkene is produced by the addition reaction of silicon alkyne and hydro-gen. Thermodynamics and dynamics computation indicated that the reaction process is exothermic, has an entropy reduction and spontaneous tendency, and the extent of reaction is large.

Key words: disilyne, addition reaction, density function, transition state, reaction channel