Absolute line intensities and first measurements of self-collisional broadening and shift coefficients in the 2ν4 band of NH3

The spectrum of ammonia near 0.793 μm

“…Similarly to Sung et al [50] , pressure shift was crudely estimated to be approximately 1/16th of self broadening. This value, which differs from the ratio of 1/10 of Sung et al [50] , is the average of the ratios of self broadening to self shift coefficients calculated from the measurements reported by Aroui et al [49] and Maaroufi et al [51] . As pressure shift coefficients tend to vary "randomly" between positive and negative extremes (see for example Fig.…”

“…As pressure shift coefficients tend to vary "randomly" between positive and negative extremes (see for example Fig. 11 of Maaroufi et al [51] ), the contribution δd of pressure shift to the uncertainty of the reported line positions was crudely estimated as δd = 0 . 68 cm −1 atm −1 × (P a v e / 16) atm ≈ 1 .…”

The 2020 edition of the GEISA spectroscopic database

“…where m = | -J, J, J+1 | for P, Q and R branches, and βi are the polynomial coefficients. The polynomial expression reproduced the observed self-broadening coefficients within an average accuracy of 9.6% for the 2ν4 band of 14 NH3 [83]. In total, 298 lines were added or updated between 3078.804070 and 3532.505190 cm -1 .…”

“…The data from the GEISA-2015 cross-sections database are plotted along with simulated spectra derived from GEISA-2015 [1], HITRAN2016 [2], Dijon SheCaSDa [120] and TheoReTS [169] line list databases. Note that we also compared with the widely used PNNL spectra [83], which are similar than to GEISA-2015 cross-sections from Varanasi of et al (Ref. [170] and private communication), but the latter contains data at higher resolution (0.03 vs. 0.112 cm -1 ) and was retained in the Figure 12.…”

“…GEISA-2020 includes, for the first time, a line list at 3.0 µm for the first-most abundant isotopologue of ammonia, 14 NH3. The 2ν4 vibrational band for this isotopologue was added using a high resolution Fourier transform investigation performed at 3.0 µm by Maaroufi et al [83]. Absolute line intensities and self-broadening and shift coefficients were measured at room temperature, for rovibrational lines ranging from 1 ≤ J ≤ 11 and 0 ≤ K ≤ 11, and located in the spectral range 3078.80407 -3532.50519 cm -1 .…”