An ab initio potential surface for the reaction N++ H2→ NH++ H

Abstract

Ab initio configuration interaction calculations using Dunning's gaussian basis set are reported for the potential energy surface for the reaction N⁺+ H₂→ NH⁺+ H. For the collinear approach of N⁺ to H₂ the ³Σ^– surface has a shallow minimum and the ³Π surface is repulsive. For C_2v geometries the ³B₂ surface is strongly repulsive and the ³A₂ surface has a shallow minimum. The ³B₁ surface has a deep well which is not adiabatically accessible at low relative energies. An avoided crossing in C_s symmetry between the ³A″ surfaces correlating with the ³A₂ and ³B₁ surfaces gives an adiabatic route to the deep potential well, but trajectory hopping is thought to be significant except at the lowest relative energies. Preliminary work on the fitting of an analytic function to attractive surfaces is discussed.