Spectroscopic study of a stationary surface-wave sustained argon plasma column at atmospheric pressure

Garcı́a, M. C.; Rodero, A.; Sola, A; Gamero, A

doi:10.1016/s0584-8547(00)00279-2

Cited by 62 publications

(64 citation statements)

References 28 publications

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“…According to the experimental results obtained by different authors, these conditions are often found in microwave discharges at atmospheric pressure. 2,3 Thus, García et al 3 obtained radially averaged measurements of the gas temperature, excitation temperature, and electron densities in an argon capillary surface-wave plasma at atmospheric pressure. Their axial results show electron densities in the range of 10 −20 m −3 , gas temperatures of 1300 K, and excitation temperatures ranging from 0.7 to 0.3 eV.…”

Section: Discussionmentioning

confidence: 99%

“…These results could explain the low values of electron temperatures reported in some works on argon microwave discharges at atmospheric pressure. 2,3 …”

Section: Discussionmentioning

confidence: 99%

“…The problem arises when the gas is sensibly cooler than the electrons, as it is the case of some microwave discharges at atmospheric pressure. 2,3 In these plasmas, the electron temperatures experimentally measured from the excitation temperature yield values that for the case of argon may be well below 0.4 eV, while the electron densities measured are over 10 20 m −3 . For these discharges, there are some experimental evidences that show that the excitation temperature can be higher than the electron temperature.…”

Section: Introductionmentioning

confidence: 94%

“…[1][2][3] As the interpretation of the data obtained with electric probes at such pressures is not clear, 4 many experimental works have focused on the use of optical emission spectroscopy ͑OES͒ as a way of characterizing the fundamental parameters of the discharge, either calculating the broadening of the emission lines to obtain the electron density, 5 modeling emission bands of some species to get the gas temperature, 6 or simply by recording the emission of the different excited states in order to get the electron temperature assuming a Bolztmann-like distribution of the population of the emitting excited levels. 3 The determination of the electron mean kinetic energy through this method is based on the identification of the excitation temperature obtained with the electron temperature. 7 This identification relies on the assumption of being in a situation close to the thermodynamic equilibrium in which all degrees of freedom share efficiently their energy.…”

Section: Introductionmentioning

confidence: 99%

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Measuring the electron temperature by optical emission spectroscopy in two temperature plasmas at atmospheric pressure: A critical approach

Yanguas‐Gil

Cotrino

González‐Elipe

2006

Journal of Applied Physics

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The measurement of the electron mean kinetic energy by identifying the electron temperature and the excitation temperature obtained by optical emission spectroscopy is theoretically studied for two temperature argon plasmas at atmospheric pressure. Using a 32-level collisional radiative model in which both electron impact and argon-impact inelastic collisions are taken into account, it has been found that under certain conditions the argon inelastic collisions may cause a decrease of the argon excitation temperature so that the relation T e Ͼ T exc Ͼ T 0 is satisfied. This inequality also appears when electron losses due to diffusion are important and the electron density is lower than its equilibrium value.

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Section: Discussionmentioning

confidence: 99%

“…These results could explain the low values of electron temperatures reported in some works on argon microwave discharges at atmospheric pressure. 2,3 …”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Measuring the electron temperature by optical emission spectroscopy in two temperature plasmas at atmospheric pressure: A critical approach

Yanguas‐Gil

Cotrino

González‐Elipe

2006

Journal of Applied Physics

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“…The Ar excitation temperature ͑T exc ͒ was obtained from the slope of the Boltzmann plot of the measured Ar I line intensities. [9][10][11] The value of T exc provides information on the atomic excitation by electron collisions. In addition, T exc generally lies between the gas temperature and the electron temperature and shows the same tendency as the electron temperature.…”

Section: A Spatial Measurements Of Plasma Parametersmentioning

confidence: 99%

Parametric study of atmospheric pressure microwave-induced Ar∕O2 plasmas and the ambient air effect on the plasma

Moon

Choe

2006

Physics of Plasmas

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A torch type microwave-induced afterglow plasma was produced at atmospheric pressure using an open-ended fused silica concentric double tube assisted by Ar and O 2 supply gases. The plasma emerged from the end of the discharge tube and was exposed to ambient air. A parametric study of the plasma characteristics was performed by measuring the temperature, density, and plasma volume as the operational parameters such as microwave power, gas flow rate, and its composition were varied. The excitation temperature ͑T exc ͒ obtained from the Ar I emission spectrum ranged from 3010 to 4350 K and the rotational temperature ͑T rot ͒ measured from the OH and O 2 diatomic molecular spectra ranged from 2250 to 3550 K. The electron density ͑n e ͒ from the H ␤ Stark broadening width at the plasma core was in the range of 6.6 to 7.6ϫ 10 14 cm −3 . The two-dimensional distribution of T exc and T rot was also obtained. Experiments while varying the Ar and O 2 gas flow rate and the O 2 / Ar ratio showed that n e was reduced but T exc was increased as the O 2 flow rate was increased. Using an additional dielectric tube for shielding the plasma from the ambient air demonstrated a significantly enlarged plasma length and lower T rot due to the nitrogen entrainment, as compared to the unshielded case.

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Microwave Plasma Systems in Optical and Mass Spectroscopy

Jankowski

Reszke²,

Broekaert

et al. 2011

Encyclopedia of Analytical Chemistry

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The art and science of microwave plasma (MWP) optical and mass spectroscopy is briefly presented including very recent advances in the field up to 2011. The use of MWPs as radiation sources for optical emission spectroscopy (OES) and atomic fluorescence spectroscopy (AFS) and as atom reservoirs for atomic absorption spectroscopy (AAS), cavity ringdown spectroscopy (CRDS), and laser‐enhanced ionization spectroscopy (LEIS) as well as ion sources for mass spectrometry (MS) is treated. Devices for producing both E‐type capacitively coupled microwave plasma (CMP)‐electrode and microwave‐induced plasma (MIP)‐electrodeless MWPs, including inductively coupled plasma (ICP)‐like H‐type plasmas, are classified and discussed, in addition to methods of their diagnostics, and results for the analytically relevant plasma parameters are presented. The means of generation of symmetrical plasmas and uses of microplasma devices are also presented with an effort to comment on general classification of microwave (MW) cavities. Further, the use of MWs for boosting of glow discharges (GDs) is treated along with other tandem sources. Methods for the introduction of gaseous, liquid, and solid samples into the MWP are discussed. They include direct vapor sampling (DVS), chemical vapor generation (CVG), and hydride generation (HG) techniques; dry aerosol generation techniques (electrothermal vaporization (ETV); spark ablation (SA); laser ablation (LA); and continuous powder introduction (CPI) as well as wet aerosol generation techniques using both solution and slurry nebulization. Special reference is made to coupling with gas chromatography (GC) and also with various separation techniques for liquids including high‐performance liquid chromatography (HPLC). The analytical figures of merit in the case of OES with low‐power and high‐power MIP, CMP, microwave plasma torch (MPT), MWP‐electrode sources including rotating field sustained plasma and H‐type MWP as well as microplasmas are given. There are also described cases of atomic absorption, fluorescence, and laser ionization with these sources. The developments in MS in the case of both low‐power and high‐power MWPs and in the case of various types of sample introduction techniques are discussed. Applications of MWP analytical spectroscopy are in the fields of biological samples with special reference to microanalysis, and of environmental and industrial samples with special emphasis on element speciation, on‐line monitoring, particle sizing, and direct solids analysis. A critical comparison of the methodology with other spectroscopic methods for the determination of the elements and their species is given.

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Spectroscopic study of a stationary surface-wave sustained argon plasma column at atmospheric pressure

Cited by 62 publications

References 28 publications

Measuring the electron temperature by optical emission spectroscopy in two temperature plasmas at atmospheric pressure: A critical approach

Measuring the electron temperature by optical emission spectroscopy in two temperature plasmas at atmospheric pressure: A critical approach

Parametric study of atmospheric pressure microwave-induced Ar∕O2 plasmas and the ambient air effect on the plasma

Microwave Plasma Systems in Optical and Mass Spectroscopy

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