The CO2 non-LTE problem taking account of the multiquantum transitions on the ν2-mode during CO2–O collisions

• Published in: Physics and chemistry of the earth. Part B, Hydrology, oceans and atmosphere Hydrology, oceans and atmosphere, 2000, Vol.25 (5-6), p.493-499
• Main Author: Ogibalov, V.P.
• Format: Article
• Language: English
• ISSN: 1464-1909
• DOI: 10.1016/S1464-1909(00)00051-4

The strong anisotopy of the interaction potential during CO2–O collisions can result in transitions in the CO2 state change of two or more ν2-quanta. The CO2 non-LTE problem of the Earth's atmosphere, taking account of these transitions, has been solved. The results have been compared with those obtained for the one-ν2-quantum transitions usually adopted during the CO2–O collisions. An increase of up to tens of Kelvin of vibrational temperatures of the CO2ν1ν2 mode manifold states in the lower thermosphere has been found, since in the case of multiquantum transitions these states can be excited by O from the ground state of the CO2 molecule. Adopting multiquantum pathway results in a considerable increase of the 15 μm band limb radiance above 100 km as compared with the one-ν2-quantum pathway case. The multiquantum transitions can result in an increased cooling rate in the 15 μm CO2 band up to 15–25 K/day at altitudes of 125–130 km. Both these consequences are demonstrated to be caused mainly by increased populations of the 0200, 0220 and 1000 states of the principal isotope of CO2.