Electric quadrupole transitions in carbon dioxide

Andrey Yachmenev, Alain Campargue, Sergei N. Yurchenko, Jochen Küpper, Jonathan Tennyson
2021 Journal of Chemical Physics  
Recent advances in high sensitivity spectroscopy have made it possible, in combination with accurate theoretical predictions, to observe, for the first time, very weak electric quadrupole transitions in a polar polyatomic molecule of water. Here, we present accurate theoretical predictions of the complete quadrupole rovibrational spectrum of a non-polar molecule CO2, important in atmospheric and astrophysical applications. Our predictions are validated by recent cavity enhanced absorption
more » ... oscopy measurements and are used to assign few weak features in the recent ExoMars Atmospheric Chemistry Suite mid-infrared spectroscopic observations of the Martian atmosphere. Predicted quadrupole transitions appear in some of the mid-infrared CO2 and water vapor transparency regions, making them important for detection and characterization of the minor absorbers in water- and CO2-rich environments, such as those present in the atmospheres of Earth, Venus, and Mars.
doi:10.1063/5.0053279 pmid:34240963 fatcat:rwj7x4dodve5fakg5iymo4kimu