Altitude Distributions of and Radiations from Certain Oxygen and Nitrogen Metastable Constituents

Abstract

The airglow emitted by certain metastable constituents N(2D), O(1D), O+(2P), and O+(2D) in the daytime atmosphere is investigated and their altitude distributions of density are obtained.The production of N(2D) atoms by dissociative recombination of N2+ with electrons is considered. Their quenching by collisions with O2 molecules is calculated, and it was shown that the calculated integrated intensity of NI 5199A line agrees with the observed value.Assuming collisional deactivation of O(1D) atoms by O2 molecules, the production rates of O(1D) by photo-dissociation of O2 in the Schumann-Range continuum at low, medium and high activities of the sun are calculated. The O(1D) distribution and rates of emission of the oxygen red line in the dayglow are also calculated. Calculated intensity at minimum activity agrees with the observed value. An order of magnitude increase in its intensity from minimum to maximum activity cannot be accounted for as due to the variations of molecular oxygen concentration and of solar extreme ultra violet flux incident upon the upper atmosphere. Contributions due to dissociative recombination of O2+ and by thermal electron impact at different levels of solar activity cannot be computed as the variation of ion composition of the ionosphere and that of electron temperature with solar cycle are not known.The production rates of metastable O+(2P) and O+(2D) ions by photoionization of O atoms are calculated. Their equilibrium distributions are computed after using the recent data of rate coefficients for ion-atom interchange and other ionic reactions. As a check, the zenith intensity of (7319-7330A) multiplet of O+ in the day airglow is calculated.