¹⁴NH model compared to observed cometary spectra. The modeled spectra have been shifted by 0.3 Å to the left for clarity. Note that the prominent features of both the observed and the modeled spectra are the (0–0) band, but some weak lines of the (1–1) and (2–2) bands are also present in the 3340–3380 Å wavelength range. (a) Comparison between the modeled NH A³Π_i − X³Σ⁻ (0–0) band (red) and the observational spectrum of Comet C/2002 T7 (LINEAR) (blue) at a heliocentric distance of R_h = 0.680 au and a heliocentric velocity of ${\dot{R}}_h$ = 15.8 km s⁻¹. (b) Comparison between the modeled NH A³Π_i − X³Σ⁻ (0–0) band (red) and the observational spectrum of Comet C/2012 F6 (Lemmon) (blue) at a heliocentric distance of R_h = 1.175 au and a heliocentric velocity of ${\dot{R}}_h$ = −23.9 km s⁻¹.