Absolute frequencies of lasing transitions in seven CO2isotopic species

The band centers, rotational constants, absolute frequencies, and vacuum wavenumbers for
¹²
C
¹⁶
O
2
,
¹³
C
¹⁶
O
2
,
¹²
C
¹⁸
O
2
,
¹³
C
¹⁸
O
2
,
¹²
C
¹⁶
O
¹⁸
O,
¹⁴
C
¹⁶
O
2
, and
¹⁴
C
¹⁸
O
2
have been simultaneously computed from 590 beat frequency measurements between pairs of adjacent
00\deg1-[10\deg0,02\deg0]
I and II band CO
2
laser transitions. The input data included the 56 beat frequencies measured between adjacent
¹²
C
¹⁶
O
2
rotational lines by Petersen et al. The absolute frequencies are directly related to the cesium frequency standard via the 29 442 483.315 (0.025) MHz 10.18 μm I-R (30) and the 32 134 266.891 (0.024) MHz 9.33 μm II-R(10) transitions in
¹²
C
¹⁶
O
2
which were measured by Evenson et al. The results described in this paper will provide the means for setting up easily reproducible secondary frequency standards in the
8.9-12.3 \mu
m wavelength band.