The molecular oxygen 118-GHz line intensity revision

Abstract

The intensity of the atmospheric diagnostic fine-structure line of the O2 molecule at 118.75 GHz is revised based on multiple measurements with a resonator spectrometer in pure O2 and O2–N2 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 ∼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.