Excitation mechanism ofNi 5199 Å lines in the day Airglow

Production rates of N(² D) metastable atoms in the daytime atmosphere have been calculated for different possible processes, using positive ion composition and reaction rate data, available presently. Emission rates of the 5199 Å doublet of Ni are calculated by separately and jointly considering the deactivation of N(² D) atoms by electrons and molecular oxygen.From a comparison of the computed results with the observational data, an attempt has been made to identify the processes of importance to the production and deactivation of N(² D). For further confirmation of the proposed mechanism the variation of integrated intensity of this radiation with solar activity has been obtained. The calculated values may be compared with intensity data obtained in future at different levels of solar activity.