Broad-linewidth laser absorption measurements of oxygen between 211 and 235 nm at high temperatures

Absorption coefficient data are presented for molecular oxygen at temperatures between 1100 and 2000 K and discrete wavelengths between 211 and 235 nm. Measurements were made behind reflected shock waves using broad-linewidth ultraviolet laser radiation generated from a frequency-quadrupled, tunable, pulsed Ti:Sapphire laser. Test mixtures consisting of 15% O2, 15% He and balance Ar were used to minimize the influence of vibrational relaxation on the reflected shock temperature. The experimental results are in good agreement with theoretical calculations and confirm that discrete features from the Schumann-Runge system dominate between 211 and 235 nm at temperatures higher than 1100 K.

Highlight► We Measured O2 absorption coefficients between 1100-2000 K and 211-235 nm. ► Measurements used broad-linewidth ultraviolet laser radiation. ► Data needed for shock tube/UV laser studies of H2O2/HO2 combustion.