Collisional Coupling of the Molecular Oxygen 16O2 Fine-Structure Lines Under Low Pressures

We consider collisional coupling between the fine-structure lines of molecular oxygen near 60 GHz under pressures of up to 20 Torr. The observation possibility of the coupling effect manifestation in the oxygen line profile is analyzed by means of numerical simulation. The signal-to-noise ratio required for direct observation of the collisional coupling and deviations of the line parameters from the tabulated values related to the indirect effect manifestation in the spectra are numerically evaluated. By the example of the overlapping profiles of the 13+ and 3− lines, the impact of collisional coupling on the doublet profile is experimentally demonstrated. The results of the analysis of experimental spectra are in good agreement with the results of numerical simulation.