Parallel Session: Theory, Contributed Talk (15min)
CC2

Calculating the non-LTE spectra of small molecules using the ExoMol Database

V. H. Clark1, S. N. Yurchenko 1*
1Department of Physics and Astronomy, UCL, London, WC1E 6BT, UK

Our new methodology [1] for calculating the non-LTE line lists of small molecules using the ExoMol Database (www.exomol.com) [2] is presented here, and compared against experimentally obtained spectra.  We use a simplistic 1D approach based on the Harmonic approximation to model the intensity pattern of the Δv = 1 and the Δv = 2 bands of 12C16O experimental spectra.  We achieve this by simulating the corresponding non-LTE vibrational populations of CO produced by formamide glow discharge [3].  We also demonstrate that our 1D model can be used for the full formamide discharge spectra between 2000 cm-1 – 5000 cm-1, and can model spectra containing up to six non-LTE molecules; including linear and non-linear triatomics, and both hetero- and homodiatomics. Excellent agreement with experiment is achieved in both cases.

[1] V. H. J. Clark, S. N. Yurchenko, Phys. Chem. Chem. Phys., 2021, 23, 11990-12004
[2] J. Tennyson, S. N. Yurchenko, et al., J. Quant. Spectrosc. Radiat. Transf., 2020, 255, 107228.
[3] A. Pastorek, S. Civiš , V. H. J. Clark, S. N. Yurchenko, M. Ferus,  J. Quant. Spectrosc. Radiat. Transf., 2021, 262, 107521