[en] Several workers have concluded that analysis of the OH infrared emission from the upper mesosphere and lower thermosphere requires population of OH(v = 5,6) by the reaction O + HO₂ → OH(v ≤ 6) + O₂. It has been stated previously that this may be unlikely if the reaction proceeds by O atom transfer rather than H atom transfer. The authors shows here that recent laboratory evidence argues convincingly that the mechanism of this reaction involves O atom transfer after formation of an HO₃ complex and that little or no population of highly vibrational levels (v ≥ 4) of OH are expected, although nonnegligible population of lower levels seems plausible. On this basis it appears that this reaction should not be contributing substantially to emission from OH(v = 5,6). The reverse reaction, OH(v ≥ 6)+O₂ → HO₂ + O, which has been suggested to be a potential sink for OH(v ≥ 6), is considered and is expected to be slow unless an HO₃ complex is formed, in which case, multiple quantum deactivation of OH is alos a likely process. Recent experimental evidence suggesting that OH(v = 4,5) may be populated by the H + O₃ → OH + O₂ reaction is discussed, although no firm conclusions about its importance can be reached