Spectroscopy of 14NH3 and 15NH3 in the 2.3 μm spectral range with a new VECSEL laser source

- A spectroscopic study of the 14NH3 and 15NH3 in the 2.3 μm region was performed.
- The newly developed Vertical External Cavity Surface Laser (VECSEL) was applied.
- The transitions line positions and relative intensities have been measured.
- 235 from 336 observed 14NH3 lines were assigned (63 for the first time).
- 183 from 244 observed 15NH3 lines were assigned (114 for the first time).

A spectroscopic study of ammonia molecule in the 2.3 μm water atmospheric window is presented. Compared to previous experimental works a narrow, broadly tunable, continuous laser source was applied in order to obtain high resolution spectra in this range. It was the first application of the newly developed Vertical External Cavity Surface Emitting Laser (VECSEL). The analysis of the absorption spectra of two different isotopologue admixtures allowed to identify 336 14NH3 and 244 15NH3 lines in the studied region from 4275 to 4340 cm−1. These data were compared to previous line list based on experimental data - the HITRAN database and the work of Urban et al., as well as to the theoretical predictions by Yurchenko et al. and Huang et al. Together for 235 14NH3 and 183 15NH3 lines a complete assignment was proposed. From those 63 14NH3 and 114 15NH3 transitions were newly assigned. The complete peaklist of transitions containing ro-vibrational state identifications is presented in Supplementary materials.