SPIKE: A computer model for the H2(D2) + F2 pulsed chemical laser

A comprehensive rate equation model for a pulsed laser pumped by the H2(D2)-F2 reaction is described. This computer simulation incorporates up to 216 kinetic reactions to describe the laser medium, which is assumed to be homogeneous and contained in a Fabry-Perot optical cavity. The first fifteen vibrational-rotational P-branch transitions from each of the lowest ten vibrational bands are monitored for possible laser action. The distinctive features incorporated in this model include: (1) the elimination of the gain-equals-loss assumption, so that it is possible to predict cavity transients and to observe gain-intensity interactions; (2) a detailed model of the Lorentz broadening, including V,J dependence, as well as distinction between various perturbing species; (3) multiquantum HF (DF) self-deactivation, which in the HF case was found important to achieve good agreement between theory and experiment. Comparisons of the prediction of this model with several small-scale experiments have indicated generally good agreement (typically within approx. 20%).