In order to further develop the theoretical research of cluster Co3MoS and to investigate the mechanism of isomerization transformation of cluster Co3MoS. Optimization calculation of the clusters was based on density functional theory and transition state theory

using quantum chemistry software and B3LYP/Lanl2dz levels as initial conditions. And the clusters was analyzed by applying thermodynamic and chemical kinetic methods. The results show that each isomerization reaction of cluster Co3MoS is mainly in the forward reaction direction

and TS3(2)→1(4)isomerization reaction is the easiest to be transformed

TS2(4)→1(2) reaction is the most difficult to be transformed

and the configurations 1(4)

1(2)

2(4)

2(2)

3(4)

3(2) can be steadily existed; the 3(2)→1(4) isomerization reaction is the most radically transformed

which limit is the largest than the other isomerization processes

the 2(4)→1(2) reaction consumes the most activation energy in the process of transformation

which is the least radical transformation; we find a link between equilibrium constants and thermodynamic stability of reactants and products; the isomerization reaction of the cluster Co3MoS can be predicted by the functional equation of energy difference and equilibrium constant

the integral form of the van't Hoff equation

and the Gibbs function.