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.

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.

THE SIMULATION OF VIBRATIONAL POPULATIONS OF ELECTRONICALLY EXCITED N2 IN TITAN’S UPPER ATMOSPHERE DURING PRECIPITATIONS OF HIGH-ENERGETIC PARTICLES

2021 ◽  
Vol 44 ◽  
pp. 122-125
Author(s):  
A.S. Kirillov ◽  
◽  
R. Werner ◽  
V. Guineva ◽  
◽  
...  
Keyword(s):  
Molecular Nitrogen ◽  
Excitation Energy Transfer ◽  
Electron Excitation ◽  
Energetic Particles ◽  
Upper Atmosphere ◽  
Radiative Processes ◽  
Calculated Volume ◽  
Ion Production ◽  
Electronically Excited ◽  
Volume Emission

We study the electronic kinetics of singlet molecular nitrogen in Titan’s upper atmosphere during precipitations of high-energetic particles. Both radiative processes and processes of electron excitation energy transfer during inelastic collisions with N2 and CH4 molecules were considered in the calculation of vibrational populations of electronically excited singlet states a'1Σu–, a1Πg, w1Δu of molecular nitrogen in the upper atmosphere of Titan. It is shown that the calculated volume emission intensities of the Lyman-Birge-Hopfield bands correlate with the profiles of the ion production rate in the atmosphere of Titan during the considered cases of electron precipitation for considered interval of the energies 30-1000 eV of magnetospheric electrons. This fact is explained by the negligible contribution of collisional processes to the vibrational populations a1Πg(v'=0-6) in the considered range of heights above 900 km.

scholarly journals The emission of the negative system of nitrogen from the upper atmosphere and the significance of the twilight flash in the theory of the ionosphere

1949 ◽  
Vol 196 (1047) ◽  
pp. 562-591 ◽  
Keyword(s):  
Transition Probability ◽  
Molecular Nitrogen ◽  
Charged Particles ◽  
High Energy ◽  
Upper Atmosphere ◽  
Ionization Mechanisms ◽  
Direct Excitation ◽  
Negative Band ◽  
Resonance Emission ◽  
Excitation Mechanisms

The cause of the emission of the negative band system of nitrogen from the upper atmosphere during twilight is investigated. A study is made of the two possible excitation mechanisms, N 2 ( X 1 Ʃ g + ) + hv →N 2 + ( B 2 Ʃ u + ) + e and N 2 + ( X 2 Ʃ g + ) + hv →N 2 + ( B 2 Ʃ u + ). It is shown that the latter is far more effective than the former, irrespective of the assumptions adopted regarding the solar flux in the unobservable spectral region. From the transition probability associated with it (which is evaluated in the appendix) combined with various intensity estimates, an upper limit is obtained for the number of N 2 + ions normally present in the E and F layers during twilight. It appears that N 2 + ions form but a minute fraction of the total ion content. The significance of this in the theory of the formation of the ionized layers is discussed. The simplest interpretation is that ionization of molecular nitrogen is unimportant; and a reasonable scheme that invokes only the ionization of oxygen atoms and molecules is available. However, by introducing certain arbitrary assumptions a more elaborate interpretation is conceivable so that the view that the E layer arises from the action of high-energy coronal photons, which ionize all atmospheric constituents, cannot be finally rejected. Various aspects of the layers are discussed, and observational and experimental work, which might yield evidence on the ionization mechanisms operative, is suggested. It is pointed out that the remarkable rarity of N 2 + ions proves conclusively that recombination between the charged particles present in the ionosphere cannot be the origin of the nocturnal radiation of the nitrogen band systems. On some occasions the resonance emission at twilight is of unusually high intensity. It is presumed that this is due to incident charged particles increasing the concentration of N 2 + ions. The possible contribution that these charged particles may make to the night-sky light by direct excitation collisions is briefly examined. Sunlit aurorae (which are essentially similar to the twilight flash) are also discussed.

Experimental Study of Low Energy e-O2 Collision Processes

1971 ◽  
Vol 26 (10) ◽  
pp. 1617-1625 ◽  
Author(s):  
F. Linder ◽  
H. Schmidt
Keyword(s):  
Angular Dependence ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
Resonance Scattering ◽  
Spectroscopic Constants ◽  
Extended Model ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
The Cross ◽  
Electronic Ground

Abstract Elastic scattering, vibrational excitation to v=1, 2, 3, 4 of the electronic ground state, and electronic excitation to the states a1Δ g and b1Σg+ of O2 have been measured in a crossed beam apparatus for collision energies from nearly 0 eV to 4 eV. Differential and integral cross sections have been determined and calibrated on an absolute scale. From 15 vibrational levels of O2-, which could be observed as resonances in the cross sections, the spectroscopic constants for the vibrational structure of O2- have been derived: ωe = 135 meV and ωeχe = 1 meV. The cross sections for vibrational excitation have the order of 10-18 cm2. eV for the larger resonance peaks. Detailed cross sections have been listed in Table 1. The half width of the resonance can be estimated to Γ ≈ 0.5 meV, which corresponds to a lifetime tof 10-12 sec for the O2- states. The angular dependence of pure resonance scattering is rather flat and not in accordance with the simplest theoretical model. An analysis of the angular dependence and of the rotational structure of the resonance in a somewhat extended model have been performed. - No electronically excited O2-states could be detected in the energy range up to 3 eV.

SURFACE-CATALYZED ATOM RECOMBINATIONS THAT PRODUCE EXCITED MOLECULES

1960 ◽  
Vol 38 (10) ◽  
pp. 1648-1651 ◽  
Author(s):  
Paul Harteck ◽  
Robert R. Reeves ◽  
Gene Mannella
Keyword(s):  
Energy Curve ◽  
Positive System ◽  
Parallel Processes ◽  
Photographic Analysis ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Excited Molecules ◽  
Crossing Point ◽  
Curve Crossing ◽  
Electronically Excited Molecules

Various metal surfaces such as nickel, cobalt, copper, and silver give rise to a reddish luminosity in a stream of N- and O-atoms. Spectroscopic and photographic analysis of these glows indicate the formation of electronically excited molecules on the metal surface which diffuse into the gas phase and radiate. Two parallel processes are involved: the formation of an NO(B2Π), which results in NO β radiation, and the formation of an [Formula: see text] which, in collision, crosses into the N2(B3Π0) state and then radiates back to the [Formula: see text] giving the N2 first positive system. The N2 first positive system observed here shows the strongest bands from v' = 8 and 6; these vibrational levels straddle the [Formula: see text] potential energy curve crossing point. This crossing-over of N2 molecules into the (B3Π0) at this point may explain the observed strong v' = 6 transition in normal N-atom recombination if it is assumed that some of the N-atoms recombine into the [Formula: see text] in addition to the [Formula: see text]state.The N2 second positive system (C3Πu → B3Π0) has also been observed over copper in an N- and O-atom stream. This is most surprising since the N2(C3Πu) has about 1.4 ev more than [Formula: see text]

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