Topography of potential-energy surfaces. DIM (diatomics-in-molecules) surfaces for H + Cl2

Abstract

Potential-energy surfaces have been calculated over the full range of nuclear configurations for the H + Cl₂ reaction using the DIM (diatomics-in-molecules) method with 14 polyatomic basis functions arising from the atomic states H(²S), Cl(²P_u), H⁺(¹S) and Cl^–(¹S). The lowest ²A′ potential-energy surface favours reaction in the collinear configuration with an activation energy in good agreement with the experimental value and a higher barrier to reaction in bent configurations. Comparison with analogous calculations on H + F₂ shows a lower activation energy for H + Cl₂, but otherwise the potential-energy surfaces have very similar topography favouring the collinear configuration for both reactions.