The neutral particle impact de-excitation cross-section of the fine structure level3P1 of atomic oxygen in the thermosphere

A new upper limit value (9.9 × 10^?21cm²) of the mean equivalent de-excitation cross-section of O(³P₁) by collision with neutral particles in the thermosphere is obtained by comparing the³P₁ state de-excitation rate due to neutral practice impact with that due to electron impact. The existing data of the cross-section obtained from the aeronomic study are compared with the theoretical data, and it indicated that the former is much less than the latter.