A dynamic threshold in the F + H2 → HF + H reaction as determined from three-dimensional quasi-classical-reverse trajectory calculations

Quasi-classical dynamic threshold energies have been determined for two important reactive transitions in the F + H₂ reaction by performing extensive three-dimensional trajectory calculations for the corresponding reverse reactions. It is found that the energetic and dynamic thresholds for the reaction F + H₂(υ = 0,j) → HF(υ = 2,j = 6) + H are the same, whereas the latter threshold is approximately 0.08 eV greater than the former one for the reaction F + H₂(υ = 0,j) → HF(υ = 3,j=1) + H. These results are in good agreement with the corresponding semi-classical threshold results which are also reported. The relationship of these quasi-classical-reverse results to experimentally measured quantities is discussed.