Accession Number : AD0486762

Title :   SPECTROPHOTOMETRY OF ATMOSPHERIC EMISSIONS.

Descriptive Note : Technical summary rept. 15 Dec-15 Mar 66,

Corporate Author : ALASKA UNIV FAIRBANKS GEOPHYSICAL INST

Personal Author(s) : Belon, Albert

Report Date : 15 MAR 1966

Pagination or Media Count : 145

Abstract : A scanning spectrophotometer equipped with a S-1 sensitive photomultiplier has been used to obtain auroral spectra in the wavelength region 6400A to 9700A. Emissions of neutrol and singly ionized molecular nitrogen, molecular oxygen, hydroxyl, and atomic lines of oxygen and nitrogen were recorded with 10 second scan times and 20 A resolution. A comparison of the relative intensities of several vibration bands of the N2 1PG system averaged over several scans with theoretical intensities and previously observed intensities reveals no evidence of selective excitation. A similar analysis of the Meinel N+2 bands also shows no evidence of selective excitation except possibly for the (1-0) band which seems enhanced on many spectra. The observations show that hydroxyl emissions are definitely associated with aurora. The association is not a direct one. There is a time lag of a few seconds between the brightening of the aurora and the enhancement of OH emissions. Similarly the OH emissions decay much more slowly (over a period of minutes) than does the aurora. This suggests that the excitation of the hydroxyl emissions in the aurora is probably due to a chemiluminescent reaction similar to that proposed for the airglow.

Descriptors :   (*AURORAE, SPECTROPHOTOMETERS), SPECTRUM ANALYZERS, ALASKA, LUMINESCENCE, INFRARED SPECTRA, IONIZATION, NITROGEN, MOLECULES, OXYGEN, SKY BRIGHTNESS, FREE RADICALS, HYDROXIDES, ATOMIC SPECTROSCOPY, CHEMILUMINESCENCE, SELECTION RULES(PHYSICS), MOLECULAR ROTATION, VIBRATION, BAND SPECTRA, MOLECULAR SPECTROSCOPY.

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE