An improved long range potential for O(1D)+H2

Several dynamics studies have indicated that the product isotopic distributions and vibrational energy distributions in the reaction O(1D)+H2(HD) are very sensitive to the long range interaction of the reactants. In this paper we report an improved calculation of the reactant region of the potential energy surface. In agreement with previous work we find no barrier to edge-on insertion (1A′ ground state water surface), but find a smaller (0.2 kcal/mol) barrier to collinear addition (1Σ+ surface) than in previous work. The long range potential obtained in the present work most closely resembles the SL3 surface.