Real atmosphere laboratory measurements of the 118-GHz oxygen line: Shape,shift, and broadening of the line

For the first time the 118-GHz line of the oxygen molecule was investigated in the laboratory under a real atmosphere. The experiment was carried out by modern resonator spectroscopy methods on the laboratory air at atmospher ic pressure. The shape of the line under the real atmosphere was found to f it the Van Vleck-Weisskopf profile within experimental accuracy. The air br oadening parameter value was defined as 2.14 +/- 0.07 MHz/Torr. The observe d atmosphere oxygen line central frequency was found to be shifted down at about 150 MHz from the line center measured at low pressures, which gives a value of -0.19 +/- 0.08 MHz/Torr for the air shift parameter. A comparison with previous investigations is presented and reprocessing of some experim ental results of other authors was carried out. Results of reprocessing agr ee with the findings of the present paper. (C) 2001 Academic Press.