The influence of electron–electron collisions on electron thermalization in He and Ar afterglow plasmas

Trunec, David; Španěl, Patrik; Smith, David

doi:10.1016/s0009-2614(03)00487-1

Cited by 24 publications

(21 citation statements)

References 19 publications

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“…At the conditions of the experiments here, electrons are rapidly thermalized 44 and none exceed about 0.5 eV. As a result, all attachment is assumed to arise from the so-called "zero-energy" peak; in the case of CF 3 arising from crossing from the ground electronic state of the neutral to the ground electronic state of the anion.…”

Section: Resultsmentioning

confidence: 99%

Electron attachment to CF3 and CF3Br at temperatures up to 890 K: Experimental test of the kinetic modeling approach

Shuman

Miller

Viggiano

et al. 2013

The Journal of Chemical Physics

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Thermal rate constants and product branching fractions for electron attachment to CF3Br and the CF3 radical have been measured over the temperature range 300-890 K, the upper limit being restricted by thermal decomposition of CF3Br. Both measurements were made in Flowing Afterglow Langmuir Probe apparatuses; the CF3Br measurement was made using standard techniques, and the CF3 measurement using the Variable Electron and Neutral Density Attachment Mass Spectrometry technique. Attachment to CF3Br proceeds exclusively by the dissociative channel yielding Br(-), with a rate constant increasing from 1.1 × 10(-8) cm(3) s(-1) at 300 K to 5.3 × 10(-8) cm(3) s(-1) at 890 K, somewhat lower than previous data at temperatures up to 777 K. CF3 attachment proceeds through competition between associative attachment yielding CF3 (-) and dissociative attachment yielding F(-). Prior data up to 600 K showed the rate constant monotonically increasing, with the partial rate constant of the dissociative channel following Arrhenius behavior; however, extrapolation of the data using a recently proposed kinetic modeling approach predicted the rate constant to turn over at higher temperatures, despite being only ~5% of the collision rate. The current data agree well with the previous kinetic modeling extrapolation, providing a demonstration of the predictive capabilities of the approach.

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Section: Resultsmentioning

confidence: 99%

Electron attachment to CF3 and CF3Br at temperatures up to 890 K: Experimental test of the kinetic modeling approach

Shuman

Miller

Viggiano

et al. 2013

The Journal of Chemical Physics

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“…The degradation or thermalization of energetic electrons in atomic and molecular moderators is an important aspect of radiation chemistry and physics (Mozumder 1999;Robson 2006), plasma processing of semiconductor devices (Petrović et al 2009), the physics of the aurora (Stamnes 1980;Basu et al 1993;Solomon 2001;Shematovich et al 2008) fundamental aspects of the approach to equilibrium (Trunec et al 2003;Sospedra-Alfonso and Shizgal 2011) and thermalization in condensed matter (Sakai 2007;White et al 2010). The electron anisotropic nonequilibrium distribution functions are often expanded in the direct product of the spherical harmonics in (θ, φ) and the Sonine-Laguerre polynomials for the reduced speed or reduced energy dependence (Kumar et al 1980;Robson and Ness 1986;Robson 2006;White and Robson 2011;Abolhassani and Matte 2012).…”

Section: Electron Thermalization; the Lorentz Fokker-planck Equation mentioning

confidence: 99%

Spectral and Pseudospectral Methods of Solution of the Fokker-Planck and Schrödinger Equations

Shizgal

2015

Scientific Computation

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“…10 At our experimental conditions the electrons are thermalized due to collisions with argon atoms. The time needed for the electron temperature decrease within 10% of neutral gas temperature was calculated using data published by Trunec et al 16 This calculated time for estimated initial electron energy of 4 eV was 1.2 ms, which corresponds to the distance of 2.4 cm in the flow tube. So, the electron temperature was equal to neutral gas temperature (300 K) in our experiment and this electron temperature was also used in the kinetic model.…”

Section: Kinetic Modelmentioning

confidence: 99%

Study of argon flowing afterglow with nitrogen injection

Mazánková

Trunec

Krčma

2013

The Journal of Chemical Physics

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In this work, the reaction kinetics in argon flowing afterglow with nitrogen addition was studied by optical emission spectroscopy. The DC flowing post-discharge in pure argon was created in quartz tube at the total gas pressure of 1000 Pa and discharge power of 60 W. The nitrogen was added into the afterglow at the distance of 9 cm behind the active discharge. The optical emission spectra were measured along the flow tube. The argon spectral lines and after nitrogen addition also nitrogen second positive system (SPS) were identified in the spectra. The measurement of spatial dependence of SPS intensity showed a very slow decay of the intensity and the decay rate did not depend on the nitrogen concentration. In order to explain this behavior a kinetic model for reaction in afterglow was developed. This model showed that C (3)Πu state of molecular nitrogen, which is the upper state of SPS emission, is produced by excitation transfer from argon metastables to nitrogen molecules. However, the argon metastables are also produced at Ar2(+) ion recombination with electrons and this limits the decay of argon metastable concentration and it results in very slow decay of SPS intensity.

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The influence of electron–electron collisions on electron thermalization in He and Ar afterglow plasmas

Cited by 24 publications

References 19 publications

Electron attachment to CF3 and CF3Br at temperatures up to 890 K: Experimental test of the kinetic modeling approach

Electron attachment to CF3 and CF3Br at temperatures up to 890 K: Experimental test of the kinetic modeling approach

Spectral and Pseudospectral Methods of Solution of the Fokker-Planck and Schrödinger Equations

Study of argon flowing afterglow with nitrogen injection

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