Rocket measurements of the 6300 Å and 3914 Å dayglow features

Rocket results are presented on the OI 6300 Å line and on the N₂⁺ 3914 Å band in the dayglow. An altitude range of 78–335 km is covered. Theoretical interpretations are given, using results of simultaneous measurements of electron density and electron temperature. The apparent brightness of the 6300 Å line at the base of the emitting region is found to be 13 kR, of which 5.5 kR are ascribed to excitation through the Schumann-Runge dissociation of O₂ by the solar UV radiations, 0.55 kR to the dissociative recombination of O₂⁺ and NO⁺ ions, and 0.03 kR to the excitation of O by thermal electrons. An additional source of excitation above 280 km is suggested. The deactivation of O(¹D) by O₂(X³Σ_g^?) is found to be appreciable below 200 km, and its rate coefficient is estimated to be 2 × 10^?10 cm³/sec. The apparent brightness of the 3914 Å band at the base of the emitting region is found to be 6.5 kR, decreasing to 3.2 kR at 330 km. Assuming that fluorescent scattering of solar radiation is the mechanism involved the distribution of N₂⁺ ions is calculated. The rate coefficients for the loss of these ions are hence calculated.