Improved Potential Energy Surface for F+H2 yields HF+H and H+H prime F yields HF+H prime

摘要

We present an improved analytic potential energy surface for the F + H2 yields FH + H and H + FH' yields HF + H' reactions. The final surface is obtained in two stages. First we create a surface, called No. 4, which is based in the F-H-H barrier region on a previous partly empirical and partly theoretical fit and is based on the F-H...H exit channel and H-F-H barrier regions on new large-basis-set configuration interaction calculations. The final surface, called No. 5 incorporates more empirical information for collinear geometries in both the F-H-H and FH...h regions but remains a good representation of the ab initio calculations for bending potentials and in the strong-interaction region. Variational-transition-state theory rate constants and WKB adiabatic barrier heights indicate that the final surface is more accurate than previous surfaces for thermal rate constants and overall reaction thresholds for F + H2 yields HF + H,F + D2 yields DF + D, and F + HD yields HF + D and for product-state thresholds for HF(n' = 3) and DF(n' = 4), where n' is the final vibrational quantum number.