Vibration-Rotation Bands of Ammonia. III. The Region 3.2–4.3 Microns

The weak absorption of NH₃ between 2373–3080 cm^—1 has been studied under high resolution, and a complete analysis given for over 1000 lines, including studies of the intensity and line width. The strongest bands (S_v⁰=0.44 and 0.20 cm^—2 atmos^—1, respectively) are ${\text{3ν}}_2^8{\text{−0}}^a\hspace{0.17em}\mathrm{and}{\text{\hspace{0.17em}3ν}}_2^a{\text{−0}}^8{\mathrm{;\nu }}_3{\mathrm{-\nu }}_2{\mathrm{\hspace{0.17em}(S}}_v^0{\text{=0.074);ν}}_3{\mathrm{+\nu }}_2{\text{−2ν}}_2{\mathrm{\hspace{0.17em}(S}}_v^0\text{=0.011);}\mathrm{and}{\mathrm{\hspace{0.17em}\nu }}_2{\mathrm{+\nu }}_4{\mathrm{\hspace{0.17em}(S}}_v^0\text{=0.06)}$ have also been located. v₂+v₄ shows anomalous intensity behavior as well as large vibration‐rotation‐inversion‐ζ‐splitting interactions. The lines in 3v₂ are 40–50% narrower than those in the microwave region, and appear symmetrical with no pressure shifts.