Rovibrational Line Lists for Nine Isotopologues of CO Suitable for Modeling and Interpreting Spectra at Very High Temperatures and Diverse Environments

In order to improve and extend the existing HITRAN database¹ and HITEMP²data for carbon monoxide, the ro-vibrational line lists were computed for all transitions of nine isotopologues of the CO molecule, namely ¹²C¹⁶O, ¹²C¹⁷O, ¹²C¹⁸O, ¹³C¹⁶O, ¹³C¹⁷O, ¹³C¹⁸O, ¹⁴C¹⁶O, ¹⁴C¹⁷O, and ¹⁴C¹⁸O in the electronic ground state up to v = 41 and J = 150. Line positions and intensity calculations were carried out using a newly-determined piece-wise dipole moment function (DMF) in conjunction with the wavefunctions calculated from a previous experimentally-determined potential energy function of Coxon and Hajigeorgiou³. Ab initio calculations and a direct-fit method which simultaneously fits all the reliable experimental ro-vibrational matrix elements has been used to construct the piecewise dipole moment function.

To provide additional input parameters into the fit, new Cavity Ring Down Spectroscopy experiments were carried out to enable measurements of the lines in the 4-0 band with low uncertainty (Grenoble) as well as the first measurements of lines in the 6-0 band (Hefei). Accurate partition sums have been derived through direct summation for a temperature range from 1 to 9000 Kelvin. A complete set of broadening and shift parameters is also provided and now include parameters induced by CO₂ and H₂ in order to aid planetary applications.