Cooling Mechanisms of the Planetary Thermospheres: The Key Role of O Atom Vibrational Excitation of CO2 and NO

Cooling due to infrared emissions from O atom excited CO2 and NO is a critically important process in the thermal budget of the terrestrial thermosphere. Increasing CO2 density due to human activity makes the role of its emission particularly worthy of quantitative evaluation. Furthermore, the O atom excited 15 microns CO2 emission has a unique role in the lower thermosphere of Venus where it is the only significant cooling mechanism; it is also an important process in the Martian thermosphere. The experimental and theoretical status of these rate coefficients is reviewed and the unsatisfactory current state of knowledge is pointed out.