Spectral line shapes of self-broadened P-branch transitions of oxygen B band

- Line shapes of O216B-band P-branch transitions were measured.
- A PDH-locked frequency-stabilized cavity ring-down spectroscopy technique was used.
- Dicke narrowing and the speed-dependent effects were included in data analysis.
- Transitions absolute frequencies were measured with the optical frequency comb.
- Line positions with about 170 kHz accuracy were obtained.

We used the Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer assisted by the optical frequency comb for systematic line-shape study of self-broadened P-branch transitions of the O216B band [b1Σg+(v=1)←X3Σg−(v=0)]. In the line-shape analysis we take into account the line-narrowing effects described by Dicke narrowing or the speed dependence of collisional broadening. The relation between the parameters describing Dicke narrowing with the use of the soft- and hard-collision models is discussed and verified experimentally in the low pressure regime using the multispectrum fitting technique. We report line positions with uncertainties of about 170 kHz, the collisional broadening coefficients with 0.45% uncertainties, and line intensities with 0.5% uncertainties. We compare these results to data available in the literature.