The 5.8 μm absorption bands for nitric acid (H14N16O3): line positions and intensities for the ν2 band at 1709.567 cm-1 and for its first associated hot bands (ν2+ν9-ν9, ν2+ν7-ν7, ν2+ν6-ν6)

This paper is the second of two back-to-back works, whose goal was to generate a more accurate linelist for the 5.8 mu m absorption band of HNO3. Here, we report improved line positions and intensities in the nu(2) cold band which is the main band in this region. For this, we recorded four high-resolution Fourier transform spectra for the nu(2) band, centered at 1709.567 cm(-1), under different experimental conditions. Using these spectra, a new extended line position analysis was performed for the nu(2) band, leading to more accurate line positions. In parallel, individual line intensities were measured. It appears that, although the nu(2) band is mainly of B-type, it also possesses a (very) weak A-type component that cannot be ignored. Overall, the line intensities in this new database are about 8% weaker than those quoted presently in the HITRAN (https://hitran.org/) or GEISA (https://geisa.aeris-data.fr/) databases. Our final linelist for HNO3 at 5.8 mu m is provided as a supplement to this paper. It includes lines from the nu(2) band together with those of the nu(2)+nu(9)-nu(9,) nu(2)+nu(6)-nu(6), and nu(2)+nu(7)-nu(7) associated hot bands that were generated during the first part of this study, described in the companion paper. [GRAPHICS]

Automated summary

This paper presents an improved study on the line positions and intensities of the 5.8 μm absorption band of HNO3, resulting in a new database with line intensities about 8% weaker than those currently quoted in HITRAN or GEISA databases. The final linelist for HNO3 at 5.8 μm is provided as a supplement to this paper, including lines from the main nu(2) band and associated hot bands from the previous part of the study.