Room temperature line lists for CO2 isotopologues with AB initio computed intensities

Abstract

We report 13 room temperature line lists for all major CO$_2$ isotopologues, covering 0-8000 \wn. These line lists are a response to the need for line intensities of high, preferably sub-percent, accuracy by remote sensing experiments. Our scheme encompasses nuclear motion calculations supported by critical reliability analysis of the generated line intensities. Rotation-vibration wavefunctions and energy levels are computed using DVR3D and a high quality semi-empirical potential energy surface (PES) [1], followed by computation of intensities using a fully \textit{ab initio} dipole moment surface (DMS). Cross comparison of line lists calculated using pairs of high-quality PES's and DMS's is used to assess imperfections in the PES, which lead to unreliable transition intensities between levels involved in resonance interactions. Four line lists are computed for each isotopologue to quantify sensitivity to minor distortions of the PES/DMS. This provides an estimate of the contribution to the overall line intensity error introduced by the underlying PES. Reliable lines are benchmarked against recent state-of-the-art measurements [2] and HITRAN-2012 supporting the claim that the majority of line intensities for strong bands are predicted with sub-percent accuracy [3]. Accurate line positions are generated using an effective Hamiltonian [4]. We recommend use of these line lists for future remote sensing studies and inclusions in databases. \vspace{15px} \small \renewcommand{\section}[2]{} \begin{thebibliography}{5} \setlength{\parskip}{0pt} \setlength{\itemsep}{0pt plus 0.3ex} \bibitem{12HuScTa.CO2} X.~Huang, D.~W. Schwenke, S.~A. Tashkun, T.~J. Lee, J. Chem. Phys. 136, 124311, 2012. \bibitem{jt613} O. ~L. Polyansky, K. Bielska, M. Ghysels, L. Lodi, N. ~F. Zobov, J. ~T. Hodges, J. Tennyson, PRL, 114, 243001, 2015. \bibitem{jt625} E. Zak, J. Tennyson, O.~L. Polyansky, L. Lodi, S.~A. Tashkun, V.~I. Perevalov, JQSRT, in press and to be submitted. \bibitem{15TaPeGa.CO2} S.~A. Tashkun, V.~I. Perevalov, R.~R. Gamache, J.~Lamouroux, JQSRT, 152, 45--73, 2015. \end{thebibliography