O_2 A-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 b^(1)Σ^(+)_(g)←X^(3)Σ^(-)_(g) (0,0) band for the rare O_2 isotopologues. The use of ^(17)O- and ^(18)O-enriched mixtures allowed for line positions to be measured for the ^(16)O^(17)O, ^(16)O^(18)O, ^(17)O_2, ^(17)O^(18)O, and ^(18)O_2 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 ^(16)O^(18)O and ^(16)O^(17)O 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