Investigation of the properties of the active medium of a CO₂ laser containing isotopically substituted carbon dioxide and nitrogen molecules

An experimental study was made of the kinetics of vibrational and translational temperatures of mixtures containing isotopically substituted molecules of carbon dioxide (¹²C¹⁶O₂, ¹³C¹⁶O₂, ¹²C¹⁸O₂, ¹³C¹⁸O₂) and of nitrogen (¹⁴N₂, ¹⁴N¹⁵N, ¹⁵N₂), and excited by a pulsed electric discharge. It was found that the efficiency of the excitation of the carbon dioxide and nitrogen vibrations in an electric discharge was independent of the isotopic composition of the active medium. Moreover, the effective rates of collisional deactivation of the energy stored in the nitrogen vibrations and in the asymmetric carbon dioxide mode were also approximately equal for all the investigated mixtures with the exception of those containing ¹³C¹⁶O₂. When a significant amount of ¹³C¹⁶O₂ was present in a mixture, the rate constant of collisional deactivation was considerably higher.