Temperature dependence of the collisional removal of O-2(b (1)Sigma(+)(g),v = 1 and 2) at 110-260 K, and atmospheric applications

The temperature dependence of the collisional removal of O-2 in the upsilon = 1 and 2 vibrational levels of the b (1)Sigma(g)(+) state by O-2, N-2, an d CO2 has been investigated over the 110-260 K temperature range. For the u psilon = 1 level, O-2 removes energy more effectively than N-2 or CO2 at al l measured temperatures. For upsilon = 2, the difference in effectiveness b etween colliders is not as great, and the removal by O-2 exhibits a substan tial positive activation energy; at 125 K O-2 in the upsilon = 2 level is r emoved about 40 times more slowly than upsilon = 1. Even with this large di fference, in the terrestrial atmosphere removal via collisions with O-2 con trols the lifetime of the vibrationally excited species. Recent atmospheric nightglow measurements performed at the W. M. Keck telescope on Mauna Kea, Hawaii, confirm the presence of O-2 in these and higher levels through obs ervation of the naturally occurring b 1 Sigma(g)(+)-X (3)Sigma(g)(-) emissi on. (C) 1999 American Institute of Physics. [S0021-9606(99)02101-7].