IMPROVED MASS-INDEPENDENT DUNHAM PARAMETERS FOR THE GROUND-STATE OF CO AND CALIBRATION FREQUENCIES FOR THE FUNDAMENTAL-BAND

New mass-independent Dunham parameters for the X1SIGMA+ ground state of the CO molecule have been deduced from a complete set of existing frequency measurements dealing with the isotopic species of CO. This work improves the results of the 1992 evaluation (J. Mol. Spectrosc. 160, 590-592, 1993) by including recent sub-Doppler frequency measurements on the CO fundamental and first hot band (to be published). The parameters given in this paper allow reproduction of nearly all the frequency measurements within their experimental uncertainties, which are close to 20 kHz for the fundamental band and about 100 kHz for the (2-1 ) band transitions. Calculated line positions for the (1-0) bands of Several isotopomers are given. (C) 1994 Academic Press. Inc.