60-GHz oxygen band: precise broadening and central frequencies of fine-structure lines, absolute absorption profile at atmospheric pressure, and revision of mixing coefficients

The 60-GHz band of 16O2 was studied at room temperature and at low (up to 4 Torr) and atmospheric pressures. Precision measurement of central frequencies, self-broadening, and N2-broadening parameters of fine-structure transitions up to N = 27 was performed by use of a spectrometer with radio-acoustic detection (RAD). The measured parameters are compared with GEISA/HITRAN databanks, MPM92, and other known data. An improved set of the oxygen fine-structure spectroscopic constants is obtained. The absorption profile was recorded in the range 45-96 GHz for laboratory air and pure oxygen at atmospheric pressure by use of a resonator spectrometer with noise level of about ± 0.05 dB/km, and used for deducing the first-order line mixing coefficients and for quantitative assessment of second-order mixing effects. A refined set of MPM parameters is derived from the new data and presented here.