Ro-vibrational Line Lists for Nine Isotopologues of CO Suitable for Modeling and Interpreting Spectra at Very High Temperatures and Diverse Environments Gang Li, Iouli Gordon, Laurence Rothman, Tan Yan, Shuiming Hu, Samir Kassi, and Alain Campargue ISMS, 16 June 2014

HITRAN96 and HITEMP95 data were mostly based on Goorvitch, ApJ Supp Series 95, (1994) solar atlas for line positions and intensities. The line positions are based on Dunham constants from Farrenq et al, JMS 149, (1991) Iintensities were based on the EDMF from Chackerian et al, Can J Phys 62, 1579 (1984). Status of data in HITRAN and HITEMP

Differences in DMFs Chackerian and Tipping JMS 99, (1983) used only v’-0 data (where v’= 0-4). They fitted it to a polynomial and then constructed Pade aproximant to restrict behavior at long range. Chackerian et al (1984) used same data supplemented with extensive  v=1, 2, and 3 data up to v=38! Chackerian and Tipping JMS 99, (1983) has by far more citations and being more regularly used!? Note, a lot of astrophysicists use data from Hure and Roueff, Astron and Astrophys Supp Series 117, (1996) which are based on ab initio EDMF of Langhoff and Bauschlicher, Jr J Chem Phys 102, (1995).

Several more recent experiments reported 5-10 % deviation from Goorvitch for 2-0 and 3-0 bands. In HITRAN2012, 12 C 16 O intensities for these bands are based on the works of Malathy Devi, et al, JQSRT 113, (2012) and Sung and Varanasi, JQSRT 83, (2004) respectively. 13 C 16 O and 12 C 18 O of 2-0 band are based on Malathy Devi, et al, J Mol Spectrosc , (2012). Corrections in HITRAN

What are the sources for potential improvement Quality and the extent of the experimental data has substantially improved since Analyses of experimental data had also improved trough more sophisticated lineshapes. Ab initio calculations are now available to restrict long-range behavior We have a new method of fitting the DMF to the experimentally observed rovibrational (rather than just vibrational) matrix elements

Direct fit approach Calculate expectation values using empirical potential of Coxon and Hajigeorgiou J. Chem. Phys. 121, 2992 (2004) Employ Le Roy’s LEVEL program. Do a least squares fit to obtain M i coefficients. Every measurement is included with appropriate weight Include long-range ab initio data and create a piecewise dipole moment function G. Li, I.E. Gordon, P.F. Bernath, and L.S. Rothman, “Direct fit of experimental ro-vibrational intensities to the dipole moment function: Application to HCl,” JQSRT 112, (2011). G. Li, I. E. Gordon, R.J. Le Roy, P.G. Hajigeorgiou, J.A. Coxon, P.F. Bernath, and L.S. Rothman, “Reference spectroscopic data for hydrogen halides. Part I: Construction and validation of the ro-vibrational dipole moment functions,” JQSRT 121, (2013)

Experimental data needed 4-0, 5-0 and 6-0 bands can easily be measured The only measurements of 4-0 band are old C. Chackerian, Jr. and F. P. J. Valero, J Mol Spectrosc 62, (1976). 5-0 band measured at high pressure (3.5 bar) -large uncertainties Chung et al, J. Phys. Chem. A 109, (2005). Factor of 2 difference with predicted intensities from Chackerian et al. 6-0 had never been observed. This work. Grenoble This work. Hefei

CRDS measurements of the 4-0 band lines in Grenoble

Input parameters 0-0 Birk, M. et al., 1996, Applied Optics 35, Zou, Q. & Varanasi, P. 2002, JQSRT 75, Malathy Devi, V. et al., 2012, JQSRT 113, , 4-1 a) Jacquemart, D. et al., 2001, Eur. Phys. J. D 14, 55. b) Wójtewicz, S. et al., 2013, JQSRT 130, CRDS measurements in Grenoble (this work). 5-0 Chung, C.-Y., Ogilvie, J. F., & Lee, Y.-P. 2005, JPCA 109, CRDS measurements in Hefei (this work).

Comparison of intensities from different sources

Intensity comparison with HITEMP

Line position comparison with HITRAN2012

Line position comparison with HITEMP

Overview of 12 C 16 O rotation-vibration line lists

This work HITRAN 2012 Goorvitch (1994) Stable isotopologues6666 Maximum v″41204 Maximum J″ Maximum  v Temperature range (K) Spectral range (cm -1 ) Number of lines752,976113,6314,606113,022 Radioactive isotopologues3None Maximum v″41 Maximum J″150 Maximum  v 11 Temperature range (K) Spectral range (cm -1 ) Number of lines376,488 Summary comparison of CO rotation-vibration line lists

 v ʹ -v″ (m) = 0.5 × (v ʹ -v″) ×   symmetric +   asymmetric   symmetric = 0.5×(    m) +    m)) Extrapolation of measured shifts   asymmetric = 0.5×(    m)    m)) Hartmann, J.-M. and Boulet, C., JCP 113, 9000 (2000) Malathy Devi et al, JQSRT 113, (2012) measurements in the 2-0 band are used as benchmark.

Test of approach on 3-0 band Measured 3-0 shifts Sung and Varanasi JQSRT 83, (2004) Extrapolated from measured 2-0 shifts Malathy Devi et al, JQSRT 113, (2012)

Conclusions  New extensive and accurate high-temperature line list of CO was calculated, including line shape parameters due to H 2 - and CO 2 - broadening  The direct fit approach to construct a dipole moment function is easy to implement while it is deemed to yield more precise results  New ab initio calculations at finer grid yield an improvement at the long range  Line positions were recalculated. However issues remain if one is looking for very high accuracy in some bands  MORE EXPERIMENTAL DATA NEEDED

Acknowledgements NASA is thanked for financial support Thank you for your attention