Cavity and chemical mechanisms in a H2+F2pulsed laser

A computer simulation of a pulsed HF laser pumped by the H2+ F2chain reaction is used to study the interaction of cavity and chemical mechanisms throughout a typical pulse. The reacting mixture contained within an optical cavity is assumed homogeneous and is approximated by a chemical kinetic model. A Boltzmann distribution for the rotational levels is assumed with lasing on each vibrational band at line center of the transition having maximum gain. During lasing, the gain is held constant and equal to the threshold gain. For simplicity, initiation is simulated by a finite initial concentration of F atoms in the gas mixture. Energy generated by the pumping reactions may be stored in the vibrational levels to meet the required gain, consumed in lasing, or lost through collisional deactivation. Relative strengths of these mechanisms are determined and the effect of varying the critical rate constants is illustrated. Laser performance is found to be insensitive to HF-HF VV transfer. As expected, variations in pumping distribution among the levels of the HF(υ) have a large effect on the pulse; the relative importance of VT deactivation of HF(υ) and VV deactivations of HF(υ) by H2vary with the relative concentrations. Lasing has a large effect on the concentration of excited HF; hence, deactivation mechanisms that are important for the zero-power case are less important during lasing.