Non-Maxwellian H and F velocity distributions in an H2–F2 reaction

Time-dependent and quasi-steady-state solutions for the velocity distribution functions of H and F atoms in a burning, homogeneous, and isotropic H2–F2 gas mixture show an increase in the rates of the H+F2 and F+H2 chemical reactions that approaches a factor of two larger than the thermalized rates. The mixture is ignited by dissociating a small fraction of the F2 molecules. Approximations to the time-dependent Boltzmann equation for the system reduce it to a form which is linear in the H and F distribution functions. This limits the solutions to early time behavior and small initial F-atom concentrations, but it allows a general picture of the burn rates to be developed from a moderate number of calculations.