Intersystem Collisional Transfer of Excitation in the Mesosphere and in the Laboratory
Final rept. 3 Nov 1983-31 Dec 1986
MARYLAND UNIV COLLEGE PARK INST FOR PHYSICAL SCIENCE AND TECHNOLOGY
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The report describes a program of experimentation involving the emission spectra of auroral species and the processes and mechanisms leading to the production of their spectra. Emphasis is on the temporal evolution of the spectrum, particularly as brought about by the intersystem collisional transfer of excitation. This latter process becomes important in auroral spectra at or near mesospheric altitudes where the collision frequency becomes comparable with the transition probability from the excited state of the auroral emitter. The experiments have been undertaken in several modes, but in every case the observational technique is that of time-resolved spectroscopy by means of which we are able to detect changes in the emitted spectrum of a collision-by- collision basis. Previously unreported effects are described which fall in the category of molecular excitation energy storage and release. Examples are given of possible superradiance where particular vibrational levels of molecular nitrogen become temporarily overpopulated with respect to those in adjacent electronic states. Keywords Aurora, Molecular, Nitrogen, Spectra, Excitation of atmospheric species.
- Atmospheric Physics