The ammonia absorption spectrum revisited between 7400 and 8600 cm-1

The room temperature absorption spectrum of ammonia is revisited between 7400 and 8600 cm^-1 on the basis of a Fourier transform absorption spectrum recorded at Université Libre de Bruxelles. The retrieved empirical line list counts more than 8400 lines and extends significantly a previous list retrieved from the same spectrum and used as main source of line parameters in the HITRAN database, in the considered region. By comparison with a variational line list, the C2018 list from Coles et al. (J Quant Spectrosc Radiat Transf 2018;219:199–212. 10.1016/j.jqsrt.2018.07.022), and validating most of the assignments by using lower state combination difference relations (LSCD), about 2798 transitions are assigned. They belong to 60 bands and correspond to about 72 % of the intensity sum in the region. The previous assignments by Barton et al. (J Mol Spectrosc 2016;325:7–12. 10.1016/j.jms.2016.05.001) which are reproduced in the HITRAN database show a poor agreement with the present results. A set of 1149 empirical values of the upper state energy levels is provided with a typical accuracy of 10^–3 cm^-1.