The observed strong 630 and 557.7 nm emissions in LAGOPEDO were produced mainly in a reaction sequence involving CO2, namely Therefore, the data shed no light on the unknown branching ratios for the ^0 + e and OH^ + e reactions. The OH* channels at 623.4, 772, and 786 nm recorded only background signals attributable to the normal twilight-sky emission. The OH*(10-4, R-branch) channel at 666 nm was chosen for the Lago- pedo experiments because there is no normal twilight radiation at that wavelength, whereas emission from the v^ = 10 level is energetically possible from the l^O-*- + e reaction (2c). The 666 nm channel recorded a weak, but nonetheless definite signal in LAGOPEDO I, but that signal was due to scattering of sunlight from ice particles. (LAGOPEDO I occurred before local sunset; LAGOPEDO II occurred after local sunset on the following night). It would be of great interest to obtain airglow measurements during the scheduled Atlas-Centaur (HEAO-C) launch, coordinated with measurements of electron density distributions, total electron content, ionospheric winds, and TIDs. A minimum set of wavelengths should include 557.7, 630, and 666 nm. The signals at all three of those wavelengths can be expected to be weak. However, measurements of their intensities would shed light on two matters, namely: 1. the branching ratios for Reactions (2a,b,c) and (4a,b,c) and 2. the percentage of water vapor that condenses out of the rocket exhaust plume and falls out of the F layer. The calculated probable minimum airglow intensity at 630 nm, as viewed from Cape Canaveral 30 minutes after launch, is 150 Rayleighs. This value, which is well above night-sky background, is based on the assumptions that 1. half of the rocket-exhaust water vapor condenses, 5 -3 2. the pre-launch F2 peak electron concentration is 10 cm , and 3. the branching ratios for Reactions (2a) and (4a) are 5 and 10%, respectively. The intensity at 666 nm could be in the kilorayleigh range. We base this statement on the fact that measure intensity in LAGOPEDO II was 90 R above background. There are several reasons for supposing that the OH production rate will be much larger in the Atlas Centaur event. We should definitely measure the 666 emission. To confirm the identification of the 666 nm as being due to 0H(10-4), it would be desirable to measure one or more related bands, such as the (10-3) at 552.7 nm, the (11-5) at 714 nm, or the (11-4) at 591.3 nm. The relative intensities are, to a limited extent, predictable from the behavior of the normal OH airglow. Thus, the (11-4) band should be more intense than the (10-3) band and less intense than the (11-5)
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