Vibrational relaxation of CO2 by O atoms

Abstract

The vibrational relaxation in CO2–Ar, CO2–O2–Ar, and CO2–O–O2–Ar mixtures was studied over the temperature range 2000–4000°K. Infrared emission measurements were made of the 4.3 μ asymmetric stretch mode and the 2.7 μ combination bands. Since all the modes of CO2 have been shown to exhibit the same relaxation time, the present measurements could be directly related to the relaxation rate for the translation-vibration excitation excitation of the bending mode. The experimental results indicate that O-atoms are approximately an order of magnitude more efficient than Ar in the relaxation of the bending mode with a collisional probability of the order of 10−2 at 3000°K.