Improved parametrization of diatomics-in-molecules potential energy surface for Na(3p 2P)+H2 → Na(3s 2S)+H2

Abstract

We report a new set of diatomics‐in‐molecules potential energy surfaces and electronically adiabatic couplings for the process Na(3p ²P) +H₂ → Na(3s ²S)+H₂. The surfaces of our previous paper [D. G. Truhlar, J. W. Duff, N. C. Blais, J. C. Tully, and B. C. Garrett, J. Chem. Phys. 77, 764 (1982)] are improved by employing a new parametrization for the ³Σ⁺ diabatic potential energy curves of NaH. The ³Σ⁺ diabatic Hamiltonian matrix Hⁿ is based on small‐basis‐set valence‐bond calculations for Hⁿ₁₂, and the diagonal elements are adjusted to yield accurate ³Σ⁺ adiabatic potential curves. The new surfaces are compared to the recent ab initio results obtained by the coupled‐electron‐pairs approximation [P. Botschwina, W. Meyer, I. V. Hertel, and W. Reiland, J. Chem. Phys. 75, 5438 (1981)], and the comparison indicates good agreement between the semiempirical and ab initio surfaces.