REEVALUATION OF THE O-2) REACTION-RATE COEFFICIENTS DERIVED FROM ATMOSPHERE EXPLORER-C OBSERVATIONS((P)

(O+(P))-P-2 is an important species for studies of the ionosphere and thermosphere: its emission at 7320 angstrom can be used as a diagnosti c of the thermospheric atomic oxygen density. Unfortunately, there are no laboratory measurements of the O and N2 reaction rates which are n eeded to determine the major sinks of (O+(P))-P-2. The reaction rates that are generally used were determined from aeronomic data by Rusch e t al. (1977) but there is evidence that several important inputs that they used should be changed. We have recalculated the O and N2 reactio n rates for (O+(P))-P-2 using recent improvements in the solar EUV flu x, cross sections, and photoelectron fluxes. For the standard solar EU V flux, the new N2 reaction rate of 3.4 +/- 1.5 x 10(-10) cm3s-1 is cl ose to the value obtained by Rusch et al. (1977), but the new 0 reacti on rate of 4.0 +/- 1.9 x 10(-10) cm3s-1 is about 8 times larger. These new reaction rates are derived using neutral densities, electron dens ity, and solar EUV fluxes measured by Atmosphere Explorer C in 1974 du ring solar minimum. The new theoretical emission rates are in good agr eement with the data for the two orbits studied by Rusch et al. and th ey are in reasonable agreement with data from five additional orbits t hat are used in this study. We have also examined the effect of uncert ainties in the solar EUV flux on the derived reaction rates and found that 15 % uncertainties in the solar flux could cause additional uncer tainties of up to a factor of 1.5 in the O quenching rate.