Airglow

Volume 2 Joseph W. Chamberlain. Physics of Volume 12 the Aurora and Airglow. 1961 ... 

The emission from electronically excited atomic and molecular oxygen is the cause of the night airglow. The atmospheric glow originates in the upper atmosphere where the pressure is so low that the radiative decay can compete favourably with the collisional deactivations. 

The sky emits radiation, known as the airglow, which during both day and night contains components resulting from optical transitions of O Ag) and 02(1Se+), and it is important to assess the possible mechanisms by which Oa may be excited to see whether they can account for the observed concentrations of singlet 02. The concentrations of possible precursors, such as 0(3P), (X1/)), and 03, probably undergo a diurnal and a seasonal variation, and it should be possible to relate the changes in [O2(1A0)] and [02(1E J+)] to the rates of excitation and loss processes. Several problems arise in these studies, since, for many of the potentially... 

The most detailed recent studies of the molecular oxygen contributions to the airglow have been concerned with the altitudinal, diurnal, seasonal, and latitudinal dependence of intensity.72,95"97,100,118 Table VIII shows some of the most reliable data available for the (0,0) bands. The unit of the Rayleigh is commonly used in airglow intensity measurements, and corresponds to an apparent emission rate of 106 photons sec"1 in a column of area 1 cm2. 

Nitric oxide is also present in the upper atmosphere its role has been reviewed by Nicolet.326-328 Because of solar radiation, important processes are photoionization, photodissociation, and the formation of electronically excited levels. The continuum seen in the night airglow has often been ascribed to reaction (4). However, both the y and / bands of NO are absent in the night airglow. Since the / and y emissions arise from... 

O( S) in the Upper Atmosphere. The presence of 0(. S ) in the upper atmosphere is indicated by the emission line at 5577 A in the airglow and aurora. The mechanism of formation and destruction of O( S) atoms has been of great interest in acronomy. Zipf (1085) gives a detailed account of various processes of O( S) in the upper atmosphere. 

To evaluate the thermodynamic and radiation properties of a natural or perturbed state of the upper atmosphere or ionosphere, the thermal and transport properties of heated air are required. Such properties are also of particular interest in plasma physics, in gas laser systems, and in basic studies of airglow and the aurora. In the latter area the release of certain chemical species into the upper atmosphere results in luminous clouds that display the resonance electronic-vibrational-rotational spectrum of the released species. Such spectra are seen in rocket releases of chemicals for upper-atmosphere studies and on reentry into the atmosphere of artificial satellites. Of particular interest in this connection are the observed spectra of certain metallic oxides and air diatomic species. From band-intensity distribution of the spectra and knowledge of the /-values for electronic and vibrational transitions, the local conditions of the atmosphere can be determined.1... 

E. B. Armstrong and A. Dalgarno, editors, The Airglow and Aurorae, Per-gamon, London, 1956. 

Airglow and Lidar Observations of Steady State Metal Layers... 

MicroChannel plate (MCP) detectors have been used in recent years as windowless X-ray and EUV detectors for astrophysical instrumentation. Successful applications have included the High Resolution Imager on the Einstein satellite (1), the EUV spectrometers on Voyager (2) and the airglow spectrometer on the P78-1 spacecraft (3). MCP s have been selected as the detectors for NASA s upcoming Extreme Ultraviolet Explorer (EUVE) satellite (4) this report was prepared as a part of the development for the EUVE satellite. 

The above process is a key element in the operation of the gain medium in the HF chemical laser [57]. It is also thought to explain the remarkable persistence and exceptionally high rotational energy (n < 32) of OH emission in Earth s airglow which has been detected some 12 h after sunset and therefore cannot be the result of direct solar excitation [58]. In the final part of this contribution, the AM method is used to demonstrate how such effects might come about in a multicollision environment that represents a rudimentary model of Earth s atmosphere. 

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