Measured and calculated absolute total cross-sections for the single ionization of CFx and NFx by electron impact

Deutsch, Hans‐Peter; Märk, T.D.; Tarnovsky, V.; Becker, K.; Cornelissen, C.; Češpiva, L.; Bonačić‐Koutecký, Vlasta

doi:10.1016/0168-1176(94)04053-2

Cited by 59 publications

(40 citation statements)

References 20 publications

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“…For molecules, theoretical and semi-theoretical models have been developed for calculating ionization cross-sections [181][182][183][184][185]187]. Progress in the measurement of molecular cross-sections [146][147][148][149] is encouraging, although incomplete.…”

Section: Summary and Recommendationsmentioning

confidence: 99%

See 1 more Smart Citation

High-temperature mass spectrometry: Instrumental techniques, ionization cross-sections, pressure measurements, and thermodynamic data (IUPAC Technical Report)

Drowart

Chatillon

Hastie

et al. 2005

Pure and Applied Chemistry

234

184

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An assessment of high-temperature mass spectrometry and of sources of inaccuracy is made. Experimental, calculated, and estimated cross-sections for ionization of atoms and inorganic molecules typically present in high-temperature vapors are summarized. Experimental cross-sections determined for some 56 atoms are generally close to theoretically calculated values, especially when excitation–autoionization is taken into account. Absolute or relative cross-sections for formation of parent ions were measured for ca. 100 molecules. These include homonuclear diatomic and polyatomic molecules, oxides, chalcogenides, halides, and hydroxides. Additivity of atomic cross-sections supplemented by empirical corrections provides fair estimates of molecular cross-sections. Causes of uncertainty are differences in interatomic distances and in shapes of potential energy curves (surfaces) of neutral molecules and of molecular ions and tendency toward dissociative ionization in certain types of molecules. Various mass spectrometric procedures are described that render the accuracy of measured thermodynamic properties of materials largely independent of ionization cross-sections. This accuracy is comparable with that of other techniques applicable under the conditions of interest, but often only the mass spectrometric procedure is appropriate at high temperatures.

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Section: Summary and Recommendationsmentioning

confidence: 99%

“…A modified additivity rule [181], viz. : (23) has been proposed in terms of the ionization cross-section for atoms and of atomic weighting factors given by: Bobeldijk et al [183] ascribe deviations from the additivity rule to mutual shielding of atoms or groups of atoms.…”

Section: Ionization Cross-sections Of Moleculesmentioning

confidence: 99%

High-temperature mass spectrometry: Instrumental techniques, ionization cross-sections, pressure measurements, and thermodynamic data (IUPAC Technical Report)

Drowart

Chatillon

Hastie

et al. 2005

Pure and Applied Chemistry

234

184

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“…II, our theory combines the Mott cross section 2 modified by the binary-encounter theory 3 for low incident energies T with the Bethe theory 4 for high T. Many models have been proposed to use this combination, [5][6][7][8] but they all require either some empirical parameters or explicit knowledge of the continuum dipole oscillator strengths of the target molecule or its constituent atoms. Some of these models require empirical parameters which are difficult to obtain, or use a large number of such parameters.…”

Section: Introductionmentioning

confidence: 99%

New model for electron-impact ionization cross sections of molecules

Hwang¹,

Kim

Rudd³

1996

The Journal of Chemical Physics

530

362

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A theoretical model for electron-impact ionization cross sections, which has been developed primarily for atoms and atomic ions, is applied to neutral molecules. The new model combines the binary-encounter theory and the Bethe theory for electron-impact ionization, and uses minimal theoretical data for the ground state of the target molecule, which are readily available from public-domain molecular structure codes such as GAMESS. The theory is called the binaryencounter Bethe (BEB) model, and does not, in principle, involve any adjustable parameters. Applications to 19 molecules, including H 2 , NO, CH 2 , C 6 H 6 , and SF 6 , are presented, demonstrating that the BEB model provides total ionization cross sections by electron impact from threshold to several keV with an average accuracy of 15% or better at the cross section peak, except for SiF 3 . The BEB model can be applied to stable molecules as well as to transient radicals. History:Received 13 A theoretical model for electron-impact ionization cross sections, which has been developed primarily for atoms and atomic ions, is applied to neutral molecules. The new model combines the binary-encounter theory and the Bethe theory for electron-impact ionization, and uses minimal theoretical data for the ground state of the target molecule, which are readily available from public-domain molecular structure codes such as GAMESS. The theory is called the binary-encounter Bethe ͑BEB͒ model, and does not, in principle, involve any adjustable parameters. Applications to 19 molecules, including H 2 , NO, CH 2 , C 6 H 6 , and SF 6 , are presented, demonstrating that the BEB model provides total ionization cross sections by electron impact from threshold to several keV with an average accuracy of 15% or better at the cross section peak, except for SiF 3 . The BEB model can be applied to stable molecules as well as to transient radicals.

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“…In a series of recent papers it could be demonstrated that this formulation (which consists of a simple analytic expression depending only on basic (known) atomic properties) may be successfully used to predict not only integrated electron impact ionization cross section function for single ionization of ground state atoms [l, 21, excited state atoms [3], radicals [4], molecules [5] and clusters [6], but also for specific inner-shell ionization processes [7]. Based on this success we have extended here the use of this semi-empirical DM formulation to ionization of the rare gases (Ne, At-, Kr and Xe) via ejection of an outer s-shell electron, e.g.…”

Section: Introductionmentioning

confidence: 99%