scholarly journals Hydroxyl (6–2) airglow emission intensity ratios for rotational temperature determination

2000 ◽  
Vol 18 (10) ◽  
pp. 1293-1303
Author(s):  
W. J. R. French ◽  
G. B. Burns ◽  
K. Finlayson ◽  
P. A. Greet ◽  
R. P. Lowe ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Rotational Temperature ◽  
Airglow Emission ◽  
Temperature Determination ◽  
Intensity Ratios

scholarly journals Hydroxyl (6−2) airglow emission intensity ratios for rotational temperature determination

2000 ◽  
Vol 18 (10) ◽  
pp. 1293-1303 ◽  
Author(s):  
W. J. R. French ◽  
G. B. Burns ◽  
K. Finlayson ◽  
P. A. Greet ◽  
R. P. Lowe ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Transition Probabilities ◽  
Rotational Temperature ◽  
Atmospheric Composition ◽  
Rotational States ◽  
Airglow Emission ◽  
Temperature Determination ◽  
Atmospheric Composition And Structure ◽  
Composition And Structure ◽  
Intensity Ratios

Abstract. OH(6–2) Q1/P1 and R1/P1 airglow emission intensity ratios, for rotational states up to j' = 4.5, are measured to be lower than implied by transition probabilities published by various authors including Mies, Langhoff et al. and Turnbull and Lowe. Experimentally determined relative values of j' transitions yield OH(6–2) rotational temperatures 2 K lower than Langhoff et al., 7 K lower than Mies and 13 K lower than Turnbull and Lowe.Key words: Atmospheric composition and structure (airglow and aurora; pressure, density and temperature)

scholarly journals A physico-chemical model to study the ion density distribution in the inner coma of comet C/2016 R2 (Pan-STARRS)

2020 ◽  
Author(s):  
Susarla Raghuram ◽  
Anil Bhardwaj ◽  
Damien Hutsemékers ◽  
Cyrielle Opitom ◽  
Jean Manfroid ◽  
...  
Keyword(s):  
Density Distribution ◽  
Electron Impact ◽  
Emission Intensity ◽  
Impact Ionization ◽  
Excitation Source ◽  
Resonance Fluorescence ◽  
Ion Density ◽  
Physico Chemical ◽  
Intensity Ratios ◽  
Ion Emission

Abstract The recent observations show that comet C/2016 R2 (Pan-Starrs) has a unique and peculiar composition when compared with several other comets observed at 2.8 au heliocentric distance. Assuming solar resonance fluorescence is the only excitation source, the observed ionic emission intensity ratios are used to constrain the corresponding neutral abundances in this comet. We developed a physico-chemical model to study the ion density distribution in the inner coma of this comet by accounting for photon and electron impact ionization of neutrals, charge exchange and proton transfer reactions between ions and neutrals, and electron-ion thermal recombination reactions. Our calculations show that CO$_2^+$ and CO+ are the major ions in the inner coma, and close to the surface of nucleus CH3OH+, CH3OH$_2^+$ and O$_2^+$ are also important ions. By considering various excitation sources, we also studied the emission mechanisms of different excited states of CO+, CO$_2^+$, N$_2^+$, and H2O+. We found that the photon and electron impact ionization and excitation of corresponding neutrals significantly contribute to the observed ionic emissions for radial distances smaller than 300 km and at larger distances, solar resonance fluorescence is the major excitation source. Our modelled ion emission intensity ratios are consistent with the ground-based observations. Based on the modelled emission processes, we suggest that the observed ion emission intensity ratios can be used to derive the neutral composition in the cometary coma only when the ion densities are significantly controlled by photon and photoelectron impact ionization of neutrals rather than by the ion-neutral chemistry.

scholarly journals Interannual dynamics in intensity of mesoscale hydroxyl nightglow variations over Almaty

2018 ◽  
Vol 4 (2) ◽  
pp. 63-68 ◽  
Author(s):  
А. Попов ◽  
A. Popov ◽  
Николай Гаврилов ◽  
Nikolay Gavrilov ◽  
А. Андреев ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Emission Intensity ◽  
Rotational Temperature ◽  
Internal Gravity Waves ◽  
Average Intensity ◽  
Interannual Variations ◽  
Average Temperature ◽  
Monthly Average ◽  
Seasonal And Interannual Variations

The method of digital difference filters is applied to the data analysis of SATI observations of hydroxyl nightglow intensity and rotational temperature at altitudes 85–90 km over Almaty (43°03' N, 76°58' E), Kazakhstan, in 2010–2017. We examine seasonal and interannual variations in monthly average values and standard deviations of variations with periods 0.4–5.4 hrs, which may be associated with internal gravity waves in the mesopause region. The monthly average temperature near the mesopause has a maximum in winter and a minimum in June. The monthly average intensity has an additional maximum in June. Standard deviation of mesoscale rotational temperature variations and characteristics of internal gravity waves are maximum in spring and autumn. The spring maximum of mesoscale OH emission intensity variations is shifted to June. Interannual variations and multi-year trends of OH rotational temperature and emission intensity may differ in detail. This may be connected with seasonal and long-term variations in the complex system of the photochemical processes, which produce the OH nightglow.

scholarly journals Employing photoluminescence to rapidly follow aggregation and dispersion of cellulose nanofibrils

The Analyst ◽  
2020 ◽  
Vol 145 (14) ◽  
pp. 4836-4843 ◽  
Author(s):  
Marcus A. Johns ◽  
Anna E. Lewandowska ◽  
Ellen Green ◽  
Stephen J. Eichhorn
Keyword(s):  
Emission Intensity ◽  
Cellulose Nanofibrils ◽  
Time Dependent ◽  
Spatially Resolved ◽  
Intensity Ratios ◽  
Confocal Spectroscopy

Multichannel confocal spectroscopy enables tracking of time dependent, spatially resolved changes in the physicochemical environment of cellulose nanofibrils due to variation in emission intensity ratios.

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