Partial Ionization Cross Sections of He, Ne, H2, and CH4 for Electrons from 20 to 500 eV

Adamczyk, B.; Boerboom, A.J.H.; Schram, B.L.; Kistemaker, J.

doi:10.1063/1.1726690

Cited by 169 publications

(65 citation statements)

References 3 publications

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“…For the remaining partial cross sections, all previous cross section measurements lie lower than the present results. The worst case is for the H ϩ cross section in which the results of Chatham et al 6 and Adamczyk et al 8 are approximately a factor of 4 lower than the present results. These low measurements are attributed to incomplete collection of the fragment ions, particularly in the cases of H 2 ϩ and H ϩ which can be seen in Fig.…”

Section: Resultscontrasting

confidence: 78%

“…Rapp, Englander-Golden, and Briglia 7 studied dissociative ionization in CH 4 by measuring the cross section for production of ions with more than 0.25 eV of initial kinetic energy. Partial cross sections for CH 4 were measured by Adamczyk et al, 8 Chatham et al, 6 and Orient and Srivastava, 9 while partial cross sections for CD 4 were measured by Tarnovsky et al 10 All previous partial cross section measurements were placed on an absolute scale by normalizing to a previously determined cross section for either methane or a rare gas. This paper reports absolute partial cross sections for electron-impact ionization of CH 4 using an apparatus and technique that allow the individual cross sections to be determined absolutely through direct measurement of all the quantities needed for their evaluation.…”

Section: Introductionmentioning

confidence: 99%

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Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV

Straub

Lin

Lindsay

et al. 1997

The Journal of Chemical Physics

112

103

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Absolute electron-impact total ionization cross sections of chlorofluoromethanes Absolute partial cross sections for electron-impact ionization of NO and NO 2 from threshold to 1000 eV Absolute partial cross sections for electron-impact ionization of H 2 O and D 2 O from threshold to 1000 eV Absolute partial cross sections for the production of CH 4 ϩ , CH 3 ϩ , CH 2 ϩ , CH ϩ , C ϩ , H 2 ϩ , and H ϩ from electron-impact ionization of CH 4 are reported for electron energies from threshold to 1000 eV. The product ions are mass analyzed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output demonstrates that all product ions are completely collected. The overall uncertainty in the absolute cross section values is Ϯ3.5% for singly charged parent ions and is slightly greater for fragment ions. Although previous measurements are generally found to agree well with the present results for CH 4 ϩ and CH 3 ϩ , almost all previous work for the remaining fragment ions lies lower than the present results and in the case of H ϩ is lower by approximately a factor of 4.

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Section: Resultscontrasting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV

Straub

Lin

Lindsay

et al. 1997

The Journal of Chemical Physics

112

103

View full text Add to dashboard Cite

show abstract

“…Figure 5 shows this comparison for non-dissociative ionization. The present cross section (continuous line) is in very good agreement with the experimental data [36,37,38,39]. The only theoretical data set available [19] is based on the Gryzinski theory combined with the Franck-Condon theory and perfectly reproduces the present data.…”

Section: Ionization Cross Sectionssupporting

confidence: 77%

Vibrationally resolved ionization cross sections for the ground state and electronically excited states of the hydrogen molecule

Wünderlich

2011

Chemical Physics

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Ionization cross sections for the hydrogen molecule have been calculated by applying the classical Gryzinski theory combined with the Franck-Condon theory. It is shown that -if the reaction channels, Franck-Condon factors and Franck-Condon densities are taken into account properly -the calculated cross sections for ionization of the molecular ground state X 1 Σ + g (v ′ = 0) are in almost perfect agreement with the latest and most reliable experimental results. A comprehensive database is established which includes vibrationally resolved cross sections for non-dissociative and dissociative ionization of the molecular ground state as well as for the first five non-repulsive electronically excited states in the molecule.

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“…Figure 9 shows a comparison of the present cross sections for non-dissociative and dissociative ionization of X 1 (v = 0) with cross-sections available in the literature. For non-dissociative ionization an excellent agreement was found between the present data and experimentally determined data [58][59][60][61] as well as theoretical [62] cross-sections.…”

Section: Electron Collision Ionization Cross-sectionssupporting

confidence: 75%

Evaluation of State-Resolved Reaction Probabilities and Their Application in Population Models for He, H, and H2

Wünderlich

Fantz

2016

Atoms

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Population models are a prerequisite for performing qualitative analysis of population densities measured in plasmas or predicting the dependence of plasma emission on parameter variations. Models for atomic helium and hydrogen as well as molecular hydrogen in low-pressure plasmas are introduced. The cross-sections and transition probabilities used as input in the atomic models are known very accurately, and thus a benchmark of these models against experiments is very successful. For H 2 , in contrast, significant deviations exist between reaction probabilities taken from different literature sources. The reason for this is the more complex internal structure of molecules compared to atoms. Vibrationally resolved models are applied to demonstrate how these deviations affect the model results. Steps towards a consistent input data set are presented: vibrationally resolved Franck-Condon factors, transition probabilities, and ionization cross-sections have been calculated and are available now. Additionally, ro-vibrational models for selected transitions are applied successfully to low-density, low-temperature plasmas. For further improving the accuracy of population models for H 2 , however, it is necessary to establish a comprehensive data set for ro-vibrationally resolved excitation cross-sections based on the most recent calculation techniques.

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Partial Ionization Cross Sections of He, Ne, H2, and CH4 for Electrons from 20 to 500 eV

Cited by 169 publications

References 3 publications

Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV

Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV

Vibrationally resolved ionization cross sections for the ground state and electronically excited states of the hydrogen molecule

Evaluation of State-Resolved Reaction Probabilities and Their Application in Population Models for He, H, and H2

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