Xenon excited state density measurements in XeCl

Time-dependent measurements of lower-level xenon-excited state densities in electron-beam pumped XeCl laser mixtures were performed. Measurements were obtained using hook interferometry under nonlasing conditions at an average excitation rate of roughly 250 kW/cu cm and e-beam pulse widths of 0.4 and 1 micron. The population differences between four different electronic transitions are examined as a function of halogen concentration. A dramatic change in the excited xenon density, due to a change in the energy flow mechanism in the XeCl kinetics caused by HCl burn-up, is observed. As long as a relatively high HCl density exists in the mixture, ion-ion recombination reactions intercept dissociative dimer-ion recombination reactions and suppress the excited xenon densities. When a certain amount of HCl is consumed, the energy flow channel switches to dimer-ion recombinations, resulting in an abrupt increase of the xenon excited state density.