A detailed discussion of the N2(C3Πu) and N2(X1Σg+) vibrational temperatures in N2glow discharges

Levaton, J.; Amorim, J.; Monna, V.; Nagai, Junsei; Ricard, A.

doi:10.1051/epjap:2004015

Cited by 31 publications

(19 citation statements)

References 9 publications

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“…The calculated temperatures θ are in good agreement with our measurements (see Table 1). We should stress that the relatively higher values found experimentally can result from the pooling of nitrogen molecular metastable that affects the experimental method to determine the vibrational temperature [17]. As will be shown, the densities of molecular metastable are high in our experimental conditions.…”

Section: Discussionmentioning

confidence: 73%

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Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

2020

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We investigated flowing N 2 DC discharges both experimentally and theoretically. The discharge gas and N 2 (X 1 Σ + g) vibrational temperatures, electron density (n e), reduced electric field (E/N), and radiative state densities were measured by optical emission spectrometry (OES) and Langmuir double probes. We formulated a discharge kinetic numerical model to calculate the densities of nitrogen species as functions of the gas residence time. We combine the experimental parameters measured in the discharge with the kinetic model to analyze different discharge conditions where E/N varies significantly. First, we analyzed the measured and calculated radiative states densities and N 2 (X 1 Σ + g) vibrational distributions at the end of the positive column. Results show good agreement between calculated and measured parameters. Then, we studied the excited molecular species densities, and neutral and excited atoms densities as functions of the discharge gas residence time. This work presents for the first time the temporal densities of excited molecular and atomic states from 10 −9 to 10 −1 s discharge residence times, calculated for experimental conditions where n e presents a low variation and E/N varies from high (94 Td) to relatively low values (48 Td). The discharge experimental conditions are discharge current of 60 mA, gas pressure of 230-530 Pa, and gas flow rate of 0.9 Slm −1. Keywords Neutral and excited atoms density. Neutral and excited molecule density. Nitrogen flowing discharges

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Section: Discussionmentioning

confidence: 73%

“…, p is the gas pressure in Torr) [9]. This procedure to obtain the electron density was utilized in several of our works on nitrogen discharges and post-discharges [8,[10][11][12][13][14][15][16][17][18]. We utilized high purity N 2 gas (99.999%) in this study.…”

Section: Experimental Setup and Resultsmentioning

confidence: 99%

Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

2020

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“…However, assuming a stationary population of the vibrational bands of N 2 ( C 3 Π u ) and the validity of the Franck‐Condon principle, the vibrational population at the N 2 ( X 1 Σ g + ) state is projected to the N 2 ( C 3 Π u ) one. Under these assumptions, the relation between T vib of these two states can be easily calculated as has been experimentally demonstrated by Levaton et al…”

Section: Experimental Setup and Optical Diagnostic Techniquesmentioning

confidence: 85%

Understanding CO₂ decomposition in microwave plasma by means of optical diagnostics

Silva

Britun

Snyders

2016

Plasma Processes & Polymers

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The growing interest to plasma‐based greenhouse gas decomposition requires the knowledge of the different kinetic mechanisms inherent in CO2 discharges and post‐discharges. This automatically involves extensive plasma diagnostics research work. Among different types of plasma diagnostics, the ones based on optical spectroscopy are of particular relevance due to their non‐intrusiveness. The recent progress in optical diagnostics of plasma‐assisted CO2 decomposition process is discussed in this work. A microwave surfaguide discharge operating at 2.45 GHz in several CO2‐containing mixtures was investigated. Optical emission spectroscopy is used to characterize the discharge area of the reactor in terms of fundamental plasma parameters. At the same time, two‐photon absorption laser‐induced fluorescence is applied for investigation of oxygen and carbon monoxide concentrations in the post‐discharge.

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“…The gas mixture composition employed in the experiments was 97% N 2 -3% Ar. The N 2 (X 1 + g ) vibrational temperature was measured from the 2nd positive system of the N 2 [21,22] and the gas temperature was measured from the 1st positive system band ratios, as described by Hochard et al [23]. The experimental set-up and optical system calibration were carefully carried out by Monna [15].…”

Section: Methodsmentioning

confidence: 99%

Measurements of N(⁴S) absolute density in a 2.45 GHz surface wave discharge by optical emission spectroscopy

Levaton¹,

Ricard²,

Henriques³

et al. 2006

J. Phys. D: Appl. Phys.

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We have generated a N 2 flowing discharge sustained by surface waves employing a 2.45 GHz high frequency source. The N 2 dissociation was studied in the discharge and post-discharge regions by optical emission spectroscopy (OES) as a function of the experimental parameters: discharge power (30-160 W) and absolute pressure (1-20 Torr), at 0.5 Slm −1 flow rate. The N(2p 3 4 S 0 ) absolute density was measured in the discharge by actinometry. We have introduced the effect of the N 2 (X 1 + g ) vibrational temperature in the actinometry equation. Such a consideration was made based on the work of Catherinot and Sy (1979 Phys. Rev. A 20 1511) which presents a profound discussion about the quenching mechanism of the N(3p 4 S 0 ) by N 2 (X 1 + g , v) states. The 811.5 nm Ar and 821.6 nm N lines, from 2p 9 → 1s 5 and 3p 4 P 0 → 3s 4 P transitions have been utilized here. Both are easily observed in the surface wave discharge. Further, the NO chemical titration was carried out in the late post-discharge furnishing the N(2p 3 4 S 0 ) absolute density in that region. The extinction point of the 580.4 nm band of the N 2 1st positive system was measured. The density values obtained by actinometry are validated by comparison with those measured in the post-discharge region. The two sets of data, function of pressure and discharge power, may be related by the mass conservation equation. The work provides the experimental N(2p 3 4 S 0 ) absolute density values as a function of power and pressure only by application of OES techniques. Moreover, we demonstrate here that the N(3p 4 P 0 ) state is quenched by N 2 (X 1 + g , v 2) molecules forming N 2 (b 1 u , v = 0) and N( 4 S) states, in agreement with Catherinot and Sy.

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A detailed discussion of the N₂(C³Π_u) and N₂(X¹Σ_g⁺) vibrational temperatures in N₂glow discharges

Cited by 31 publications

References 9 publications

Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

Understanding CO₂ decomposition in microwave plasma by means of optical diagnostics

Measurements of N(⁴S) absolute density in a 2.45 GHz surface wave discharge by optical emission spectroscopy

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A detailed discussion of the N2(C3Πu) and N2(X1Σg+) vibrational temperatures in N2glow discharges

Cited by 31 publications

References 9 publications

Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

Neutral and Excited Molecules and Atoms Densities in the Positive Column of Flowing N2 DC Discharges

Understanding CO2 decomposition in microwave plasma by means of optical diagnostics

Measurements of N(4S) absolute density in a 2.45 GHz surface wave discharge by optical emission spectroscopy

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A detailed discussion of the N₂(C³Π_u) and N₂(X¹Σ_g⁺) vibrational temperatures in N₂glow discharges

Understanding CO₂ decomposition in microwave plasma by means of optical diagnostics

Measurements of N(⁴S) absolute density in a 2.45 GHz surface wave discharge by optical emission spectroscopy