Vibrational energy transfer in O2(v=2–8)–O2(v=) collisions

Sharma, Renuka; Welsh, Judith A.

doi:10.1063/1.3132588

Cited by 3 publications

(3 citation statements)

References 37 publications

(39 reference statements)

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“…Unfortunately, this is not sufficient for the description of transitions involving higher v 3 vibrational quantum number. For the missing reactions that cannot be found in literature, we determine the rate coefficients based on either SSH (Schwartz, Slawsky, Herzfeld) theory [69] or Sharma-Brau (SB) scaling [70] accounting for short-range contributions or describing transitions dominated by long-range interactions, respectively and ensuring that the obtained rate coefficients are not larger than the gas kinetic collision frequency (2.4 × 10 −10 cm 3 s −1 for CO 2 at 300 K [71]). However, note that the rate coefficients for collisionless V-V transfers can be higher than the gas kinetic collision processes as reported for SF 6 in [72].…”

Section: Vibrational Quenching On the Wallmentioning

confidence: 99%

Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

Fromentin

Silva

Dias

et al. 2023

Plasma Sources Sci. Technol.

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This work explores the effect of O2 addition on CO2 dissociation and on the vibrational kinetics of CO2 and CO under various non-equilibrium plasma conditions. A self-consistent model, previously validated for pure CO2 discharges, is further extended by adding the vibrational kinetics of CO, including electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) and vibration-to-vibration energy exchange (V-V) processes. The vibrational kinetics considered include levels up to v = 10 for CO and up to v1 = 2 and v2 = v3 = 5, respectively for the symmetric stretch, bending and asymmetric stretch modes of CO2, and accounts for e-V, V-T in collisions between CO, CO2 and O2 molecules and O atoms and V-V processes involving all possible transfers involving CO2 and CO molecules. The kinetic scheme is validated by comparing the model predictions with recent experimental data measured in a DC glow discharge, operating at pressures in the range 0.4 - 5 Torr (53.33 - 666.66 Pa). The experimental results show a lower vibrational temperature of the different modes of CO2 and a decreased dissociation fraction of CO2 when O2 is added to the plasma but an increase of the vibrational temperature of CO. On the one hand, the simulations suggest that the former effect is the result of the stronger V-T energy-transfer collisions with O atoms which leads to an increase of the relaxation of the CO2 vibrational modes; On the other hand, two main mechanisms contribute to the lower CO2 dissociation fraction with increased O2 content in the mixture: the back reaction, CO(a3Πr) + O2 → CO2 + O and the recombinative detachment O- + CO → e + CO2.

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Section: Vibrational Quenching On the Wallmentioning

confidence: 99%

Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

Fromentin

Silva

Dias

et al. 2023

Plasma Sources Sci. Technol.

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“…Collisions of N 2 ( v ≥ 2) with ground state N 2 ( v = 0), mediated by dispersion interactions [ Sharma and Welsh , ], rapidly thermalize vibrationally excited N 2 ( v ) produced by the process shown in equation :

N_{2} ((), v \geq 2) + N_{2} ((), 0) \to N_{2} ((), v - 1) + N_{2} ((), 1) - 28.6 \times ((), v - 1) {cm}^{- 1} .

…”

Section: New Mechanismmentioning

confidence: 99%

A new mechanism for OH vibrational relaxation leading to enhanced CO₂ emissions in the nocturnal mesosphere

Sharma

Wintersteiner

Kalogerakis

2015

Geophysical Research Letters

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On the basis of experimental and theoretical studies, this paper proposes a new mechanism that contributes to nocturnal 4.3 µm CO2 emissions. It suggests that collisions of ground state O atoms with highly vibrationally excited OH(v), produced by the reaction of H with O3, remove a substantial fraction of the OH(v) vibrational energy by a fast, spin‐allowed, multiquantum vibration‐to‐electronic energy transfer (ET) process that generates O(1D): OH(v ≥ 5) + O(3P) → OH(0 ≤ v′ ≤ v − 5) + O(1D). The electronically excited O(1D) atom is subsequently deactivated by collisions with N2 in a fast spin‐forbidden ET process that leaves the N2 molecule with an average of 2.2 vibrational quanta. Finally, the vibrational excitation of N2 is transferred by a fast, near‐resonant vibration‐to‐vibration ET process to the asymmetric stretch (v3) mode of CO2, which promptly radiates near 4.3 µm.

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“…58,61,[63][64][65][66][67] etc. as well as theoretical calculations by[62,[68][69][70] we managed to create a database of the rate coefficients and quantum yields of reaction products with the participation of O 2 (b1 …”

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confidence: 99%

Model of Daytime Oxygen Emissions in the Mesopause Region and Above: A Review and New Results

Yankovsky

Vorobeva

2020

Atmosphere

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Atmospheric emissions of atomic and molecular oxygen have been observed since the middle of 19th century. In the last decades, it has been shown that emissions of excited oxygen atom O(1D) and molecular oxygen in electronically–vibrationally excited states O2(b1Σ+g, v) and O2(a1Δg, v) are related by a unified photochemical mechanism in the mesosphere and lower thermosphere (MLT). The current paper consists of two parts: a review of studies related to the development of the model of ozone and molecular oxygen photodissociation in the daytime MLT and new results. In particular, the paper includes a detailed description of formation mechanism for excited oxygen components in the daytime MLT and presents comparison of widely used photochemical models. The paper also demonstrates new results such as new suggestions about possible products for collisional reactions of electronically–vibrationally excited oxygen molecules with atomic oxygen and new estimations of O2(b1Σ+g, v = 0–10) radiative lifetimes which are necessary for solving inverse problems in the lower thermosphere. Moreover, special attention is given to the “Barth’s mechanism” in order to demonstrate that for different sets of fitting coefficients its contribution to O2(b1Σ+g, v) and O2(a1Δg, v) population is neglectable in daytime conditions. In addition to the review and new results, possible applications of the daytime oxygen emissions are presented, e.g., the altitude profiles O(3P), O3 and CO2 can be retrieved by solving inverse photochemical problems when emissions from electronically vibrationally excited states of O2 molecule are used as proxies.

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Vibrational energy transfer in O2(v=2–8)–O2(v=) collisions

Cited by 3 publications

References 37 publications

Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

A new mechanism for OH vibrational relaxation leading to enhanced CO₂ emissions in the nocturnal mesosphere

Model of Daytime Oxygen Emissions in the Mesopause Region and Above: A Review and New Results

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Vibrational energy transfer in O2(v=2–8)–O2(v=) collisions

Cited by 3 publications

References 37 publications

Study of vibrational kinetics of CO2 and CO in CO2–O2 plasmas under non-equilibrium conditions

Study of vibrational kinetics of CO2 and CO in CO2–O2 plasmas under non-equilibrium conditions

A new mechanism for OH vibrational relaxation leading to enhanced CO2 emissions in the nocturnal mesosphere

Model of Daytime Oxygen Emissions in the Mesopause Region and Above: A Review and New Results

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Product

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Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

Study of vibrational kinetics of CO₂ and CO in CO₂–O₂ plasmas under non-equilibrium conditions

A new mechanism for OH vibrational relaxation leading to enhanced CO₂ emissions in the nocturnal mesosphere