Abstract: The termolecular reaction H_2+2I→2HI has been studied by quantum chemi- cal pseudopotential ab initio method. The transition state was assumed to be li- near:
I ——R_2 H ——R_1 H ——R_2 I
The reaction system was represented by a wave function consisting of two confi- gurations, i.e.
ψ=C_1ψ1+C_2ψ_2
where ψ_1 and ψ_2 are determinants describing the electronic state of reactant and product respectively. By solving a second order secular equation for fixed values of R_1 and R_2, we can obtain a point on the potential energy surface. Keeping R_1 constant and varying R_2 (or vice versa), an energy ...