Persistent band heads of second positive system of N2 and first negative system of N2+ in the spectra of lightning


By Nayanjyoti Dehingia, Gaurangadhar Baruah



The spectra of cloud to ground lightning flash data have been analyzed for the three year period 2005-2008, for a geographical area centered on Dibrugarh (27o.29/ N, 94o.58/ E), Assam, India. Of the fifty spectra recorded on a Quartz spectrograph thirty exhibited only continuum. The remaining spectra indicated the clear presence of the persistent band heads of the second positive band system of molecular nitrogen. The spectra of lightning with reference to the (0,0) bands of the 2nd positive system of nitrogen has been recorded for the first time with the help of a conventional Q-24 medium quartz spectrograph. It would follow that molecular nitrogen is the predominate species which reveals itself as a persistent band heads belonging to the 2nd positive system.  The (0,0) band of the second positive system is observed in most of the  spectra, but with different intensities. In some cases the first negative system of singly ionized molecular nitrogen (N2+) is also observed. It is evident that the spectra photographed with lightning furnish information of great value in regard to the identification of the material present in the atmosphere.


Click here to download the complete article in PDF Format