High temperature collisional broadening of the oxygen A-band for partners O2, N2, and Ar

The oxygen A-band (b¹${\Sigma }_g^{+}$ $\leftarrow$ X³${\Sigma }_g^{-}$) line positions, strengths, and shapes have been measured with great accuracy at room temperature for a variety of mixtures. This work seeks to extend measurements of lineshape to higher temperatures for broadening partners O₂, N₂, and Ar using a new pathlength amplification technique for shock tubes. A reflected shock tube is used to generate conditions of interest up to 2500 K in O₂ and 1800 K in mixtures of O₂, N₂, and Ar. Absorption lineshapes are measured directly using scanned direct absorbance spectroscopy and fit using a Voigt lineshape profile. Self broadening is reported for selected quanta in both R and P branches for J” 4–46 and for nitrogen and argon broadening for J” 12–46. An empirical broadening model is fit and reported for each broadening partner based on measurements from this work and room temperature data from previous works.