scholarly journals Electronic kinetics of molecular nitrogen and molecular oxygen in high-latitude lower thermosphere and mesosphere

2010 ◽  
Vol 28 (1) ◽  
pp. 181-192 ◽  
Author(s):  
A. S. Kirillov
Keyword(s):  
Molecular Oxygen ◽  
High Latitude ◽  
Molecular Nitrogen ◽  
Lower Thermosphere ◽  
Rate Coefficients ◽  
Triplet States ◽  
Quenching Rate ◽  
Principal Mechanism ◽  
Auroral Electron ◽  
Electronically Excited

Abstract. Total quenching rate coefficients of Herzberg states of molecular oxygen and three triplet states of molecular nitrogen in the collisions with O2 and N2 molecules are calculated on the basis of quantum-chemical approximations. The calculated rate coefficients of electronic quenching of O2* and N2* molecules show a good agreement with available experimental data. An influence of collisional processes on vibrational populations of electronically excited N2 and O2 molecules is studied for the altitudes of high-latitude lower thermosphere and mesosphere during auroral electron precipitation. It is indicated that molecular collisions of metastable nitrogen N2(A3Σu*) with O2 molecules are principal mechanism in electronic excitation of both Herzberg states c1Σu&minus, A'3Δu, A3Σu+ and high vibrational levels of singlet states a1Δg and b1Σg+ of molecular oxygen O2 at these altitudes.

scholarly journals Electronically excited molecular nitrogen and molecular oxygen in the high-latitude upper atmosphere

2008 ◽  
Vol 26 (5) ◽  
pp. 1159-1169 ◽  
Author(s):  
A. S. Kirillov
Keyword(s):  
High Latitude ◽  
Molecular Nitrogen ◽  
Upper Atmosphere ◽  
Wavelength Shift ◽  
Auroral Ionosphere ◽  
Not Given ◽  
Auroral Electron ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Vibrational Population

Abstract. Relative vibrational populations of triplet B3Πg, W3Δ,sub>u, B'3Σu− states of N2 and the b1Σg+ state of O2 are calculated for different altitudes of the high-latitude upper atmosphere during auroral electron precipitation. It is shown that collisional processes cause a wavelength shift in the distribution of relative intensities for 1PG Δv=3 sequence of N2. The calculation of relative populations for vibrational levels v=1–5 of the b1Σg+ state in the auroral ionosphere has not given an agreement with experimental results. Preliminary estimation of the contribution of the reaction O2++NO to the production of O2(b1Σg+) on the basis of a quantum-chemical approximation does not allow for an explanation of the observable vibrational population of the b1Σg+ state in the aurora.

The effect of atmospheric temperature on the calculations of the intensity of oxygen emissions in the framework of the Barth mechanism: sensitivity study

2020 ◽  
Author(s):  
Valentine Yankovsky
Keyword(s):  
Molecular Spectroscopy ◽  
Lower Thermosphere ◽  
Basic Research ◽  
Atmospheric Temperature ◽  
Sensitivity Study ◽  
Rate Coefficients ◽  
Effect Of Temperature ◽  
Kinetic Temperature ◽  
Altitude Range ◽  
Quenching Rate

<p>In the nightglow of the atmosphere in the altitude range of 90-105 km, the Barth’ mechanism is the dominant mechanism of excitation of oxygen emissions [1].</p><p>The source of oxygen emissions in this altitude range is the three-body reaction of the association of oxygen atoms. The rate coefficient of this reaction, as well as the collision quenching rate coefficients of the excited oxygen components O(<sup>1</sup>S), O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>), O<sub>2</sub>(a<sup>1</sup>Δ<sub>g</sub>) depend on the kinetic temperature of the gas. The method of sensitivity analysis for complex photochemical systems developed in [2] allows one to comprehensively consider the temperature dependence of the processes of excitation and quenching for each excited component. Analytical expressions will be obtained for the sensitivity coefficients of the intensities of these emissions depending on temperature and altitude. The formulas obtained are also suitable for estimation of the effect of temperature on the contribution of the Barth’ mechanism to atmospheric dayglow. This work was supported by the Russian Foundation for Basic Research (grant RFBR No. 20-05-00450 A).</p><p>1. Krasnopolsky V. A. (2011), Excitation of the oxygen nightglow on the terrestrial planets, Planetary and Space Science, 59, 754-766, doi: 10.1016/j.pss.2011.02.015.</p><p>2. Yankovsky V. A., Martyshenko K. V., Manuilova R. O., Feofilov A. G. (2016), Oxygen dayglow emissions as proxies for atomic oxygen and ozone in the mesosphere and lower thermosphere, Journal of Molecular Spectroscopy, 327, 209-231, doi: 10.1016/j.jms.2016.</p>

Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives

2012 ◽  
Vol 16 (04) ◽  
pp. 413-422 ◽  
Author(s):  
Zafar Iqbal ◽  
Abimbola Ogunsipe ◽  
Tebello Nyokong ◽  
Alexey Lyubimtsev ◽  
Michael Hanack ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Molecular Oxygen ◽  
Ground State ◽  
Single Photon ◽  
Electronic Absorption Spectra ◽  
Zinc Phthalocyanine ◽  
Triplet States ◽  
Collisional Quenching ◽  
Quenching Rate ◽  
Yield Values

The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.

scholarly journals The simulation of vibrational populations of electronically excited N2and O2molecules in the middle atmosphere of the Earth during precipitations of high-energetic particles.

2020 ◽  
Author(s):  
A.S. Kirillov ◽  
◽  
R. Werner ◽  
V. Guineva ◽  
◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Electronic Excitation ◽  
Middle Atmosphere ◽  
Molecular Nitrogen ◽  
Inelastic Collisions ◽  
Transfer Processes ◽  
The Earth ◽  
Electronically Excited ◽  
Kinetics Of

We study the electronic kinetics of molecular nitrogen and molecular oxygen in the middle atmosphere of the Earth during precipitations of high-energetic protons and electrons.The role of molecular inelastic collisions in intermolecularelectron energy transfer processes is investigated.It is shown that inelastic molecular collisions influence on vibrational populations of electronically excited molecular oxygen. It is pointed out on very important role of the collisions of N2(A3u+) with O2molecules on the electronic excitation of Herzberg states of molecular oxygenat the altitudes of the middle atmosphere.

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

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