Altitude dependence of the vibrational distribution of in the nightglow and the possible effects of vibrational excitation in the formation of O(1S)

1984 ◽  
Vol 62 (8) ◽  
pp. 780-788 ◽  
Author(s):  
I. C. McDade ◽  
E. J. Llewellyn ◽  
R. G. H. Greer ◽  
G. Witt
Keyword(s):  
Vibrational Relaxation ◽  
Vibrational Excitation ◽  
Relaxation Model ◽  
Terrestrial Atmosphere ◽  
Transfer Step ◽  
Vibrational Distribution ◽  
Altitude Dependence ◽  
Vibrational Levels ◽  
The Individual

A simple vibrational relaxation model that reproduces the observed vibrational distribution of the [Formula: see text] Herzberg II bands in the terrestrial nightglow is used to derive the altitude profiles of the fractional populations in the individual vibrational levels. Through consideration of these profiles it is shown that if [Formula: see text] is the Barth precursor of O(1S) in the nightglow then, at least in the terrestrial atmosphere, the higher vibrational levels appear to be more effective in the Barth transfer step than the lower vibrational levels.

Vibrational excitation in

1986 ◽  
Vol 64 (12) ◽  
pp. 1657-1663 ◽  
Author(s):  
Tom G. Slanger
Keyword(s):  
Charge Transfer ◽  
Vibrational Excitation ◽  
Transfer Mechanism ◽  
Charge Transfer Mechanism ◽  
Vibrational Distribution ◽  
Vibrational Levels ◽  
Excitation Processes ◽  
Oxygen Atoms

Excitation processes for [Formula: see text] in aurorae, in the nightglow, and in laboratory sources are discussed. It is shown that the observed vibrational distribution in aurorae is consistent with the [Formula: see text] + NO charge-transfer mechanism. Arguments are presented for the case that quenching of O2(b) in vibrational levels above ν′ = 1 is rapid, and that therefore the auroral source is much larger than previously supposed. It is suggested that oxygen atoms are an efficient quencher for O2(b) levels above ν′ = 1.

scholarly journals New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium

2018 ◽  
Vol 36 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Konstantinos S. Kalogerakis ◽  
Daniel Matsiev ◽  
Philip C. Cosby ◽  
James A. Dodd ◽  
Stefano Falcinelli ◽  
...  
Keyword(s):  
Thermodynamic Equilibrium ◽  
Vibrational Relaxation ◽  
Local Thermodynamic Equilibrium ◽  
Vibrational Excitation ◽  
Kinetic Temperature ◽  
Population Distributions ◽  
Vibrational Levels ◽  
Non Local ◽  
Relationship Of ◽  
The Relationship

Abstract. The question of whether mesospheric OH(v) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(v) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-v) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(v) rotational population distributions. Rapid OH(high-v) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-v) rotational distributions. The effective rotational temperatures of mesospheric OH(v) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. Dedicated to Tom G. Slanger in celebration of his 5 decades of research in aeronomy.

VIBRATIONAL RELAXATION IN DISSOCIATING DIATOMIC GASES

1963 ◽  
Vol 41 (5) ◽  
pp. 717-723 ◽  
Author(s):  
M. McChesney
Keyword(s):  
Vibrational Relaxation ◽  
Vibrational Excitation ◽  
Thermal Dissociation ◽  
Boltzmann Distribution ◽  
Anharmonic Oscillators ◽  
Distribution Law ◽  
Relaxation Equation ◽  
Vibrational Levels ◽  
Equilibrium Level ◽  
Theoretical Analyses

This article questions the available theoretical analyses relating to the vibrational excitation of a dissociating gas which assume that the gas dissociates from vibrational level populations given by the Maxwell–Boltzmann distribution law. The two theories of thermal dissociation are briefly outlined and it is shown that either theory gives non-equilibrium-level populations. Furthermore, the use of a simple relaxation equation to describe the vibrational excitation of anharmonic oscillators in high vibrational levels is questioned.

scholarly journals Subauroral red arcs as a conjugate phenomenon: comparison of OV1-10 satellite data with numerical calculations

1997 ◽  
Vol 15 (8) ◽  
pp. 984-998 ◽  
Author(s):  
A. V. Pavlov
Keyword(s):  
Electron Density ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Atomic Oxygen ◽  
Major Ions ◽  
Integral Intensity ◽  
Rate Coefficients ◽  
Vibrationally Excited ◽  
Vibrational Distribution ◽  
Vibrational Levels

Abstract. This study compares the OV1-10 satellite measurements of the integral airglow intensities at 630 nm in the SAR arc regions observed in the northern and southern hemisphere as a conjugate phenomenon, with the model results obtained using the time-dependent one-dimensional mathematical model of the Earth ionosphere and plasmasphere (the IZMIRAN model) during the geomagnetic storm of the period 15–17 February 1967. The major enhancements to the IZMIRAN model developed in this study are the inclusion of He+ ions (three major ions: O+, H+, and He+, and three ion temperatures), the updated photochemistry and energy balance equations for ions and electrons, the diffusion of NO+ and O2+ ions and O(1D) and the revised electron cooling rates arising from their collisions with unexcited N2, O2 molecules and N2 molecules at the first vibrational level. The updated model includes the option to use the models of the Boltzmann or non-Boltzmann distributions of vibrationally excited molecular nitrogen. Deviations from the Boltzmann distribution for the first five vibrational levels of N2 were calculated. The calculated distribution is highly non-Boltzmann at vibrational levels v > 2 and leads to a decrease in the calculated electron density and integral intensity at 630 nm in the northern and southern hemispheres in comparison with the electron density and integral intensity calculated using the Boltzmann vibrational distribution of N2. It is found that the intensity at 630 nm is very sensitive to the oxygen number densities. Good agreement between the modelled and measured intensities is obtained provided that at all altitudes of the southern hemisphere a reduction of about factor 1.35 in MSIS-86 atomic oxygen densities is included in the IZMIRAN model with the non-Boltzmann vibrational distribution of N2. The effect of using of the O(1D) diffusion results in the decrease of 4–6% in the calculated integral intensity of the northern hemisphere and 7–13% in the calculated integral intensity of the southern hemisphere. It is found that the modelled intensities of the southern hemisphere are more sensitive to the assumed values of the rate coefficients of O+(4S) ions with the vibrationally excited nitrogen molecules and quenching of O+(2D) by atomic oxygen than the modelled intensities of the northern hemisphere.

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.

scholarly journals The Schumann-Runge O2 Emission, Following Visible Multiphoton Excitation of NO2

1983 ◽  
Vol 1 (2) ◽  
pp. 113-130 ◽  
Author(s):  
Y. Matsumi ◽  
Y. Murasawa ◽  
K. Obi ◽  
I. Tanaka
Keyword(s):  
Excited State ◽  
Excitation Spectrum ◽  
Wavelength Range ◽  
Vibrational Relaxation ◽  
Multiphoton Excitation ◽  
Vibrationally Excited ◽  
Multiphoton Process ◽  
Vibrational Levels ◽  
Visible Laser ◽  
X State

The Schumann-Runge emission (B3Σu− − X3Σg−) of oxygen was observed in the wavelength range of 220–300 nm, when NO2 was irradiated with a focused visible laser (470–580 nm). The excitation spectrum of the emission also showed the Schumann-Runge transition from highly excited vibrational levels (v″ = 22–26) of the X state to the v′ = 1–3 levels of the B state of oxygen. The highly vibrationally excited O2 (Evib ≃ 30000 cm−1) is once produced through a multiphoton process of NO2 and then absorbs one more photon. The resulting excited state of O2 emits fluorescence in the UV region. Even at 40 torr of NO2, no rotational-vibrational relaxation in the B state was observed. The mechanism of the multiphoton process is discussed.

Vibrational Relaxation Model of Diatomic Molecules for DSMC Simulation

2000 ◽  
Vol 2000.13 (0) ◽  
pp. 403-404
Author(s):  
Hiroki YAMAGUCHI ◽  
Nobuyuki TSUBOI ◽  
Shu TAKAGI ◽  
Yoichiro MATSUMOTO
Keyword(s):  
Vibrational Relaxation ◽  
Diatomic Molecules ◽  
Relaxation Model ◽  
Dsmc Simulation

The measurement of rapid rate processes by kinetic spectroscopy during a photolysis flash; vibrational relaxation of NO X 2 II from levels v 2

1972 ◽  
Vol 328 (1575) ◽  
pp. 515-527 ◽  
Keyword(s):  
Optical Density ◽  
Vibrational Relaxation ◽  
Energy Exchange ◽  
Vibrational Energy ◽  
Excited Level ◽  
Vibrational Levels ◽  
Order Of Magnitude ◽  
Rate Processes ◽  
Kinetics Of ◽  
Good Agreement

The recording of transient changes in optical density that take place during the period of a photolysis flash can, in principle, allow measurement of the kinetics of photo-processes having half-lives an order of magnitude less than the rise or decay time of the flash itself. The construction and use of a sensitive, ‘split-beam’ kinetic spectrophotometer is described, which permits the detection of transient changes in optical density > 0.01 and the measurement of half-lives >1 (us. The apparatus has been used to study the relaxation of NOX 2 II from its first and second excited vibrational levels in the presence of N 2 0 or CH4 and/or Ar. The efficiency of vibrational energy exchange with N 2 0 decreases with the vibrational quantum number of the excited level and this is shown to be consistent with the reduction in the vibrational spacing caused by anharmonicity. The measured collision numbers are in good agreement with those calculated on the baste of an empirical correlation (Callear 1965).

scholarly journals Pulsed Co2-Laser Excitation of 03/02 Mixtures at Pressures From 0.16 to 1.20 Bar

1990 ◽  
Vol 10 (4) ◽  
pp. 207-226 ◽  
Author(s):  
B. Raffel ◽  
J. Wolfrum
Keyword(s):  
Laser Excitation ◽  
Vibrational Temperature ◽  
Laser Energy ◽  
Vibrational Excitation ◽  
Double Resonance ◽  
Uv Absorbance ◽  
Relaxation Model ◽  
Laser Fluences ◽  
Pulsed Co2 Laser ◽  
Fluence Dependence

An investigation is presented of the transient vibrational excitation of O3 in the collision dominated regime initiated by pulsed CO2-laser radiation. IR-UV-double resonance experiments and measurements of the absorbance for the CO2-laser lines 9P18, 20, and 22 were carried out. Mixtures of O3 (p=17 mbar) with 02 were investigated at pressures of 160 mbar ≤Pmixt≤1200 mbar and laser fluences of 0.10 J/cm2≤Fin< 2 J/cm2 . The results are interpreted by numerical simulations in terms of a comprehensive excitation/relaxation model based upon SSH-theory. Concerning the evolution of the excitation, simulated transients of the UV-absorbance compare well with the corresponding observed signals. The saturation of the absorbing O3-transitions is demonstrated by the measured fluence dependence of the absorption coefficient at the laser wavelengths. The extent of the 03-excitation can be deduced according to the model from the maximum vibrational temperature Tm reached in the v1- and v3-oscillators. Tm accessible via the UV-transients and also via the absorbed laser energy in the case of slow relaxation at 160 160​mbar≤Pmixt≤340 mbar. In this range both techniques result in the same values for Tm. The experimental and the corresponding simulated Tm depend exponentially on the laser fluence (Tm =const . F¯in0.3) provided Tm>400​K being also confirmed up to Pmixt=1200 mbar by the observed UV-transients.

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