SynopsisWe present precise line-shape measurements of the nitrogen-broadened P9 P9 oxygen B-band transition occurring near 689 nm. Data were obtained using the optical frequency comb-assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer. Several line-shape models describing physical effects such as Dicke narrowing, the speed dependence of collisional broadening and shifting, and the correlation between velocity- and phase-changing collisions were used in the analysis. The multispectrum fitting technique is used to minimize correlation between line-shape parameters. Observed line narrowing is mostly determined by the speed dependence of the collisional broadening.
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