The visible absorption spectrum of NO₃ measured by high‐resolution Fourier transform spectroscopy

The visible absorption spectrum of the nitrate radical NO 3 has been measured using high‐resolution Fourier transform spectroscopy. The spectrum was recorded at 294 K using a resolution of 0.6 cm −1 (corresponding to 0.026 nm at 662 nm) and covers the 12600–21500 cm −1 region (465–794 nm). Compared to absorption spectra of NO 3 recorded previously, the new data show improvements concerning absolute wavelength calibration (uncertainty 0.02 cm −1 ), and spectral resolution. A new interpretation and model of the temperature dependence of the strong (0‐0) band around 662 nm are proposed. The results are important for long‐path tropospheric absorption measurements of NO 3 and optical remote sensing of the Earth's atmosphere from space.