The molecular oxygen 118-GHz line intensity revision

The intensity of the atmospheric diagnostic fine-structure line of the O-2 molecule at 118.75 GHz is revised based on multiple measurements with a resonator spectrometer in pure O-2 and O-2-N-2 mixture at pressures ranging from 250 to 1500 Torr and temperatures within 278-327 K. The resulting intensity of 1.000(3).10(-25) cm/molec confirms the earlier measurements and allows decreasing the uncertainty down to similar to 0.3%. An excellent agreement with the result of calculations presented in HITRAN is demonstrated, suggesting that the 10%-20% uncertainty recommended by the database for all fine structure lines is too large.