The atomic oxygen emission at 63 μ is analyzed between 50 km and 250 km for several atmospheric models. The frequency integrated intensities and the volume emission rates are computed and discussed in connection with experimental and theoretical investigations of the atomic oxygen distribution. It is shown that radiative transfer should be used below 150 km. If an infrared emission occurs near the tropopause, the radiative transfer solutions leads to an infrared heating near the mesopause. A reduction factor is introduced for comparison with an optically thin atmosphere.