TOWARDS AN ACCURATE INFRARED LINELIST FOR CO${_2}$ AND ISOTOPOLOGUES

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Following the "Best Theory + High-resolution Experimental Data" strategy, we have completed an initial CO${_2}$ infrared (IR) line list, denoted Ames-1. A procedure similar to the one used for ammonia nderline{\textbf129}, 214304 (2008); \textit{J. Chem. Phys.} nderline{\textbf134}, 044320/044321 (2011).} is adopted to generate a global potential energy surface (PES), including various small corrections such as scalar relativity, extrapolation to the one-particle basis-set limit, and a higher-order correlation correction, followed by refinement using accurate high-resolution laboratory data. We will discuss limitations in the use of HITRAN data for the refinement step. The current PES yields uncertainties of 0.01-0.02 cm$^{-1}$for \textit{J}=0-117 $^{12}$C$^{16}$O${_2}$ energy levels up to 13,845 cm$^{-1}$ above the zero-point level. Comparisons between Ames-1, HITRAN, and CDSD will be presented for room temperature as well as selected higher temperatures. Results for $^{13}$C, $^{14}$C, $^{17}$O, and $^{18}$O isotopologues will be presented, and the accuracy for isotopologues will be discussed. Limitations of the current PES and the Ames-1 line list together with strategies to improve these will be discussed.

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Author Institution: MS 245-1, NASA Ames Research Center, Moffett Field, CA, 94035; SETI Institute, 189 Bernardo Ave, Suite 100, Mountain View, CA, 94043; MS T27B-1, NASA Ames Research Center, Moffett Field, CA, 94035; Laboratory of Theoretical Spectroscopy, V.E. Zuev Institute of Atmospheric Optics, SB, Russian Academy of Science, 634055, Tomsk, Russia

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