Vibrational Nonequilibrium in Carbon-Dioxide Electric - Lasers.

An experimental and theoretical investigation of the vibrational nonequilibrium in a CO2-N2-He electric discharge was performed under strong nonequilibrium conditions. A tuneable, spectrally pure CO2 laser was constructed and used with a double-beam diagnostic system to measure small signal 10.6 and 9.6 micron gain in an electric discharge laser amplifier tube. Vibrational temperatures of the symmetric and bending modes were determined by combining the gain measurements with a direct measurement of the vibrational temperature of the asymmetric mode using a band reversal. A theoretical analysis was formulated using all significant collisional and radiative processes. Transfer rates for all of these processes have been previously established to within a factor of 2, with the exception of the symmetric-bending mode coupling rate which has an experimental discrepancy of a factor of 400. This coupling rate was used as the only adjustable parameter in the theory to match the theoretically predicted 10.6 and 9.6 micron gains to experimental values.