SIMBAD references

High-precision millimeter and submillimeter wave measurements were performed on two ¹⁷O isotopically substituted carbon monoxide species, i.e., ¹²C¹⁷O and ¹³C¹⁷O. Covering the frequency region from 100 GHz to 1 THz, the accuracy achievable is estimated to be ±5 kHz in the Doppler-limited mode and ±1 kHz for sub-Doppler-resolution measurements. From a weighted least-squares fit, the following molecular rotational parameters for ¹²C¹⁷O and ¹³C¹⁷O were obtained: for ¹²C¹⁷O,

B₀=56,179.99110(28)MHz, D₀=174.330(6)kHz;

and for ¹³C¹⁷O,

B₀=53,644.7906(29)MHz, D₀=158.918(19)kHz;

in both instances, the H₀values were kept fixed to IR data. The oxygen ¹⁷O nucleus exhibits a sizeable electric nuclear quadrupole moment, which has been measured for both isotopomers, i.e., eQq(¹²C¹⁷O)=4.298(44)MHz and eQq(¹³C¹⁷O)=4.355(182)MHz. The high precision of the Lamb dip measurements allowed us to observe additional small hyperfine effects caused by the magnetic moment of the ¹⁷O nucleus. These precision measurements allowed the determination of the nuclear spin-rotation constant C_I(¹⁷O)=-31.60(72)Hz for ¹²C¹⁷O, solely from the Cologne data set. The highly precise transition frequencies reported here should warrant deep interstellar searches for the two molecules ¹²C¹⁷O and ¹³C¹⁷O. The latter has not been detected in space until very recently. On the basis of our laboratory data, we were able to report the discovery of ¹³C¹⁷O (by Bensch and coworkers) along with the observations of two additionalrare CO isotopomers including ¹²C¹⁷O and ¹²C¹⁸O toward core C of the ρ Ophiucus molecular cloud.