Energetic nitrogen atoms play a significant role in the chemistry and
thermal balance of the thermosphere. The nocturnal energy distribution
is calculated and the importance of including the center of mass moti
on is demonstrated. The center of mass motion gives rise to an extende
d component of fast atoms. The calculation of the energy distribution
includes the loss of energetic nitrogen atoms in reactions with molecu
lar oxygen. The density of energetic atoms and their energy distributi
on are strong functions of local time, altitude, and latitude.