SEMIEMPIRICAL ENERGY SURFACE FOR H3

A semiempirical potential-energy surface has been generated from the London equation by evaluating the Coulomb and exchange integrals using a method which takes into account the effective orbital overlap as a function of internuclear distance. A single adjustable parameter is used to fit the calculated activation energy to the observed value. The surface is symmetrical and very flat over the saddle-point region, which leads to much lower values for the probability of H-atom tunneling through the barrier.