Thermal emission from the deep atmosphere of Venus can be detected on the nightside around 2.3 μm. The analysis of this radiation requires a reliable knowledge of the absorption in the far wings of the nearby allowed CO2 bands and of the absorption due to collision‐induced bands. We measured absorption coefficients for pure CO2 at pressures varying from 30 to 60 bars in the frequency range 3910–4570 cm−1 at 297.5 K. Values between 1.0 and 1.6 × 10−7 cm−1 amagat−2 are found in the 4100–4500 cm−1 interval where emission from the Venus nightside occurs. The comparison of experimental results with synthetic spectra calculated from a line by line code demonstrates that the Lorentzian line shape strongly overestimates the observed absorption, whereas the use of a χ factor extrapolated from the 3800–4000 cm−1 region does not provide enough opacity.
JGR-Atmospheres includes physics and chemistry of the atmosphere, as well as the atmospheric-biospheric, lithospheric, and hydrospheric interface.
AGU's Vision is a worldwide scientific community that advances, through unselfish cooperation in research, an understanding of Earth and space that is used for the benefit of humanity.
