Topography of potential energy surfaces: DIM surface for H+F2

Abstract

Potential energy surfaces have been calculated over the full range of nuclear configurations for the H+F2 reaction using the DIM method with the 14 polyatomic basis functions arising from the atomic states H(2S), F(2Pu), H+(1S) and F−(1S). The lowest potential energy surface agrees with the LEPS surface only in the collinear configuration. Qualitatively different forms are observed in strongly bent configurations which are determined by configuration interaction with low-lying surfaces corresponding to electronically excited states which are inadequately treated in the LEPS formulation. Trajectory calculations using the LEPS surface at higher collision energy or for vibrationally excited F2 are likely to give erroneous results when broadside configurations contribute to the scattering.