Two new potential energy surfaces for the F+H₂ reaction

We have adjusted a new potential energy surface for the reaction F+H ₂→FH+H and isotopic analogs such that, as compared to the widely used Muckerman no. 5 potential energy surface, rate constants and activation energies are in better agreement with experiment, and the bending potential is in better argreement with ab initio calculations, while the product vibrational energy distribution for thermal collisions is not changed greatly. The adjustments are carried out using a combination of variational transition state theory, the correlation of product vibrational energy distributions with mixed energy release as defined by Polanyi and co-workers, and quasiclassical trajectory calculations. The new surface has a classical barrier height of 0.74 kcal/mol.