Measurement of the Submillimeter-Wave Rotational Transition of Oxygen at 424 kMc/sec

The submillimeter-wave rotational transition N=1→3, J=2→2 of oxygen has been measured at a frequency of 424 763.80 ±{} 0.20 Mc/sec. The millimeter-wave fine-structure frequencies for the $N=1$ and $N=3$ states have been remeasured with high precision. From the results the rotational constant of oxygen B₀=43100.589±0.022 Mc/sec has been derived.