I get that $CO_2$ absorbs radiation at a frequency that is associated with the energy levels of atoms bumping around and the molecule rotating, and by electrons.
1) Maybe that is not thermal energy, because it is not of the translation of the whole molecule, which would be heat? So it does not get "hotter" before it reradiates?
2) Maybe a little of the IR absorbed into linear motion, or heat, but not much, so the CO2 remains approximately at the same temperature?
3) In summary, does the CO2 get hotter?
4) (In a discussion about Global Warming, I claimed that the CO2 is analogous to a mirror, and that heating up is a secondary effect, if any.)
5) Thank you for your answers. With them and my other reading I hope to clarify: From K. McClary I see that the CO2 could quickly reradiate the photon and so would have netted no gain in energy. But, assuming that you mean 10-9 milliseconds for an average time for a collision, which could transfer the energy to other rotation, vibration, and translation modes, more generally the energy of the original photon gets spread out in a local temperature increase of the nearby molecules. When that energy is radiation in random directions, half of it goes downward towards the Earth. That "one half" is the dominant effect for AGW. Then when the Earth's surface warms, it in turn warms the lower atmosphere.
If the radiation in/out of the CO2/air is balanced, the temperature of the air would not directly increase. Is it balanced, and if not, is that small imbalance unimportant?