Optical emission spectroscopy of He–N<sub>2</sub>mixture plasma

Rehman, Najeeb Ur; Masood, Anum; Anjum, Zakia; Ahmad, Ishaq; Khan, Muhammad Arshad; Zakaullah, M.

doi:10.1080/10420150.2015.1083993

Cited by 5 publications

(2 citation statements)

References 18 publications

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“…Another possible species is the N 2 radical. Although optical emission spectroscopy measurements have mainly been studied in plasmas of pure nitrogen gas, 108 as well as Ar–N 2 109 and N 2 –He 110 mixtures, the appearance of N 2 molecular species in laser-produced plasmas of azo and diazo compounds, as well as hydrazines and hydrazones, is entirely possible. Notwithstanding, we found no references to these investigations via optical emission spectroscopy in the literature.…”

Section: Excited Matter: From Prompt To New Species Through Transientmentioning

confidence: 99%

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Moros

Laserna

2019

Appl Spectrosc

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Optical emission of laser-produced plasmas from solids, liquids, and gases, from their fundamentals to their potential applications, has been comprehensively reported in multiple research manuscripts, reviews, and books. There are nevertheless enough serious unanswered issues and questions still present on what at first sight seemed to be much easier, the laser-induced breakdown spectroscopy (LIBS) of organic compounds. Ideally, for all organic molecules, one would expect homologous emission spectra, differing only in the presence or absence of signals associated to the containing elements and their intensity relative to their content. Yet, the reality is much more complex. In laser-induced plasmas of organic compounds, a broad variety of species may be formed depending on the irradiation parameters. Furthermore, there is not a uniform breakage for all the molecules constituting the ablated mass. At once, the plasma is a dynamic entity per se, which implies that the spatial distribution of each species in the source plasma is different. In addition, multiple circumstances and mechanisms may contribute to the extinction of some species and the formation of new ones. Thus, the surrounding atmosphere where the plasma evolves and the time elapsed from its formation also have a strong influence on the spectral signature gathered. In essence, any change in any of the variables involved in the cycle of an organic plasma, from those causing its formation to those governing its expansion, defines a new scenario that lead to a different LIBS spectrum for a same organic compound. The present paper reviews the common emitting species populating the laser plasmas of organic compounds, the routes to their formation, mostly those related to the production of diatomic radicals, the dynamics of such species, in space and time, and the physical parameters that they confer to the plasma. Concurrently, the influence that the structures of the molecular solids and the set of excitation variables may exert on the optical emissions observed is also discussed. Finally, some details on the modeling of organic plasmas are provided.

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Section: Excited Matter: From Prompt To New Species Through Transientmentioning

confidence: 99%

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Moros

Laserna

2019

Appl Spectrosc

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“…Figure b shows the variation of electron temperature T e with oxygen concentration in the mixture. In order to measure T e via the Boltzmann plot, He‐I emission lines were employed . It is clear from the figure that T e increases with increase in O 2 concentration in the mixture.…”

Section: Resultsmentioning

confidence: 99%

Optical characterization of atmospheric‐pressure plasma needle

Fatima

Rehman

Younus

et al. 2017

Contrib. Plasma Phys

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The atmospheric-pressure plasma needle is a promising source that can be used efficiently for different industrial applications. A radio frequency (RF) (13.56 MHz) generator was used to generate a He-O 2 /Ar mixture plasma. The ground-state oxygen atomic density [O] was calculated as a function of discharge parameters by "actinometry". The Ar-I (2p 1 → 1s 2 ) line at 750 nm and the O-I ( 3 P → 3 S) line at 844 nm were used to estimate the [O] atomic density. The rotational temperature T R of He-O 2 /Ar mixture was measured from the rotational levels of the "first negative system" (FNS) N + 2 (B 2 Σ + u , ′ → X 2 Σ + g , ′′ ) by using the "Boltzmann plot". The effect of discharge parameters on the atomic oxygen density [O] and the gas temperature was monitored. These results show that [O] density increases with RF power and O 2 concentration, but decreases with the gas flow rate. Whereas the gas temperature increases with increase in the input RF power, it decreases with increase in the gas flow rate and O 2 concentration in the mixture. Since the [O] atomic density contributes to plasma-based biomedical applications, the proposed optimum conditions for plasma-based decontamination of heat-sensitive materials in the present study are 0.6% oxygen, 500 sccm flow rate, and 26 W RF power.

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A hypothetical approach toward laser-induced high-density polyethylene pyrolysis: a review

Nabi,

Khawaja,

Liu

et al. 2024

Sustainable Materials and Technologies

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Optical emission spectroscopy of He–N₂mixture plasma

Cited by 5 publications

References 18 publications

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Optical characterization of atmospheric‐pressure plasma needle

A hypothetical approach toward laser-induced high-density polyethylene pyrolysis: a review

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Optical emission spectroscopy of He–N2mixture plasma

Cited by 5 publications

References 18 publications

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Laser-Induced Breakdown Spectroscopy (LIBS) of Organic Compounds: A Review

Optical characterization of atmospheric‐pressure plasma needle

A hypothetical approach toward laser-induced high-density polyethylene pyrolysis: a review

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Product

Resources

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Optical emission spectroscopy of He–N₂mixture plasma