Seasonal-latitudinal distributions of the populations of the states O2(b1, v = 0 - 2) in the daytime mesosphere and lower thermosphere

<p>In the last decade, it was shown that volume emission rates (VMR) for transitions from the levels O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v’ = 0 – 2) to the levels O<sub>2</sub>(X<sup>3</sup>Σ<sup>-</sup><sub>g</sub>, v’’) can be used as proxies for retrieving the altitude profiles of [O(<sup>3</sup>P )], [O<sub>3</sub>] and [CO<sub>2</sub>] in the mesosphere and lower thermosphere (MLT) [1, 2]. Despite the fact that, in single experiments, radiation in the bands 762, 688, and 628 nm corresponding to the abovementioned transitions were observed (e. g., [3]), no systematic measurements of the intensities of these emissions have yet been performed. The main source of excitation of the levels O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v’ = 0 – 2) is the energy transfer from the excited O(<sup>1</sup>D) atom, along with the resonant absorption of solar radiation in these bands in the mesosphere.</p><p>In the framework of the YM2011 model of electronical-vibrational kinetics of the excited products of O<sub>2</sub> and O<sub>3</sub> photolysis, using systematic SABER satellite experimental data on the [O (<sup>1</sup>D)] altitude profiles we calculated the altitudinal-latitudinal distributions of the O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v’ = 0 – 2) concentrations  and VMR in the corresponding bands, using the 2010 data as an example. It was shown that there is a seasonal dependence of the altitude profiles of the concentrations of excited states O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v’ = 0 – 2) obviously related to the seasonal changes of [O(<sup>3</sup>P)] and [O<sub>3</sub>] profiles.</p><p>This work was supported by the Russian Foundation for Basic Research  (grant RFBR No. 20-05-00450 A).</p><p>1. 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><p>2. Yankovsky V. A., Vorobeva E. V., Manuilova R. O. (2019), New techniques for retrieving the [O(3P)], [O3] and [CO2] altitude profiles from dayglow oxygen emissions: Uncertainty analysis by the Monte Carlo method, Advances in Space Research, 64, 1948–1967, https://doi.org/10.1016/j.asr.2019.07.020</p><p>3. Torr M. T., Torr D. G. (1985), A Preliminary Spectroscopic Assessment of the Spacelab 1/Shuttle Optical Environment, J. Geophys. Res. A 90, 1683–1690, https://doi.org/10.1029/JA090iA02p01683.</p>

The behavior and modelling of the vibrational-to-translational temperature ratio at long time scales in CO2 vibrational kinetics

Reaction kinetics study of the vibrational-to-translational temperature ratio of CO2, a crucial variable to achieve an energetically efficient dissociation in non-thermal plasma.

Гелиевое послесвечение без метастабильных частиц

The results of a spectroscopic study of the afterglow of a pulsed barrier discharge in helium with a small admixture of neon, which creates a plasma with a low density of metastable particles, are discussed. The early stage of the afterglow of such a discharge is free of processes involving metastables and has a purely recombination nature. The characteristics of the afterglow are interpreted on the basis of the model taking into account vibrational kinetics and dissociative recombination of molecular ions. A comparison of experimental data and model solutions for collisional-radiative recombination of atomic ions and dissociative recombination leads to the conclusion in favor of the latter process as a source of the excited atoms.