Vibrational nonequilibrium in carbon dioxide electric discharge lasers

An experimental and theoretical investigation of vibrational nonequilibrium in the CO2 electric discharge laser was performed. The vibrational temperature for each vibrational mode of CO2 was measured under a variety of discharge conditions. Measurements indicate nonequilibrium between ν1 and ν2 can be significant. Possible causes for the apparent nonequilibrium which were theoretically examined included anomalously high gain on certain transitions which has been attributed to overlapping hot band contributions, use of different optical broadening cross sections, use of different electron−vibration excitation cross sections, and the effect of uncertainty in all V−V and V−T transfer rates. The most likely cause of the measured nonequilibrium was found to be a lack of strong coupling between the ν1 and ν2 modes.