One equilibrium structure and harmonic frequencies and force constant for the PuH2 molecule have been optimized using Gaussian 98 program with B3LYP method. Analytical potential energy function for PuFk system was derived using many-body expansion method. Molecular reaction dynamics for the collision Pu(~7F_g) + H_2(X~1Σ_g~+,0,0) have been studied basedon the analytical potential energy function of PuH_2(X~7A_1) by Monte-Carlo quasi-classical trajectory approach. The results for the collision process indicate that the main channel, is an elastic collision.

Key words: PLUTONIUM, HYDROGEN, REACTION KINETICS, REACTION MECHANISM, POTENTIAL ENERGY