O2A-band line parameters to support atmospheric remote sensing. Part II: The rare isotopologues

Frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) was employed to measure over 100 transitions in the R-branch of the b1Σg+←X3Σg−(0,0) band for the rare O2 isotopologues. The use of 17O- and 18O-enriched mixtures allowed for line positions to be measured for the 16O17O, 16O18O, 17O2, 17O18O, and 18O2 isotopologues. Simultaneous fits to the upper and lower states were performed for each isotopologue using the FS-CRDS positions supplemented by microwave, millimeter, submillimeter, terahertz, and Raman ground state positions from the literature. Positions, line intensities, pressure broadening parameters, and collisional narrowing parameters are reported for the 16O18O and 16O17O isotopologues which are based upon the present study and our earlier FS-CRDS work (Long et al. J Quant Spectrosc Radiat Transfer 2010;111:2021 [18] and Robichaud et al. J Phys Chem A 2009;113:13089 [15]). The calculated line intensities include a term for the observed Herman-Wallis-like interaction and correct a frequency-dependent error, which is present in current spectroscopic databases.

► Employed frequency-stabilized cavity ring-down spectroscopy (FS-CRDS). ► Measured rare O2 isotopologue transitions in the b1Σg+←X3Σg−(0,0) band. ► Line lists are presented for 16O18O and 16O17O, which include collisional narrowing. ► The calculated line intensities include the observed Herman-Wallis-like interaction. ► They also correct a frequency-dependent error found in existing spectroscopic databases.