scholarly journals Direct and Dissociative Ionization Cross Section of Oxygen Molecule from Threshold to 10 KeV

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1365-1368
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Threshold Energy ◽  
Theoretical Data ◽  
Oxygen Molecule ◽  
Dissociative Ionization ◽  
Ionization Cross ◽  
Section Data ◽  
Ionization Cross Sections

Due to abundant applications of ionization in various fields of applied sciences, it’s desirable to calculate absolute ionization cross sections of various atoms or molecules. In this literature, we have calculated the absolute direct and dissociative ionization cross sections of the oxygen molecule from threshold energy to 10,000 eV by using revisited Jain-Khare semi-empirical approach. In this literature, the total direct and absolute ionization cross section data have compared with easily available experimental and/or theoretical data. The present results give a better account for the ionization cross sections up to higher incident electron energies.

Inner-Shell Ionization Cross Sections

1990 ◽  
Vol 48 (2) ◽  
pp. 6-7
Author(s):  
C. J. Powell
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Relativistic Correction ◽  
Bethe Equation ◽  
Ionization Cross ◽  
Section Data ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Image Position ◽  
Shell Ionization

Values of cross sections for ionization of inner-shell electrons by electron impact are required for electron probe microanalysis, Auger-electron spectroscopy, and electron energy-loss spectroscopy. The present author has reviewed measurements and calculations of inner-shell ionization cross sections. This paper is an update and summary of these previous reviews.It is convenient to start with the Bethe equation for inner-shell ionization cross sections which is frequently used (and misused) in x-ray microanalysis:(1)where σnℓ is the cross section for ionization of the nℓ shell with binding energy Enℓ by incident electrons of energy E. The terms bnℓ and cnℓ are the Bethe parameters discussed further below. It has been assumed in the derivation of Eq. (1) that E ≫ Enℓ ; this requirement will also be discussed. Finally, it has been assumed here that E is low enough (≲50 keV) so that a relativistic correction is unnecessary.The extent to which a given set of measured or calculated cross-section data is consistent with Eq. (1) can be determined from a Fano plot in which σnℓE is plotted versus ℓnE; if such a plot is linear, Eq. (1) is consistent with the data and values of the Bethe parameters can be easily derived.

Ionization Cross Sections for Quantitative Electron Probe Microanalysis

2001 ◽  
Vol 7 (S2) ◽  
pp. 672-673
Author(s):  
C. Merlet ◽  
X. Llovet ◽  
S. Segui ◽  
J.M. Fernández-Varea ◽  
F. Salvat
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Ionization Cross Section ◽  
Ionization Cross ◽  
Quantitative Electron Probe Microanalysis ◽  
Ionization Cross Sections ◽  
Semi Empirical ◽  
Quantitative Epma

Quantitative procedures in electron probe microanalysis (EPMA) require the knowledge of various atomic parameters, the most fundamental of which is the ionization cross section. A number of semi-empirical, approximate analytical formulas have been proposed to calculate the ionization cross section. The simplicity of these formulas makes them suitable for quantitative EPMA procedures. However, it is difficult to assess their reliability because of the lack of accurate experimental data. Indeed, inspection of currently available data reveals that they are still scarce for many elements and, when they are available, one usually finds significant discrepancies between data from different authors. Fortunately, the inaccuracies in the semi-empirical cross section formulas used in EPMA have only a small effect on the analytical results when standards are used. Nonetheless, in quantitative EPMA studies at low overvoltages or using standardless methods, the evaluated compositions largely depend on the adopted ionization cross sections and, therefore, knowledge of accurate ionization cross sections is a requisite for the development of improved quantification methods.

Ionization by protons in the energy range 100 to 450 keV

1963 ◽  
Vol 274 (1358) ◽  
pp. 365-370 ◽  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Axial Magnetic Field ◽  
High Energy ◽  
Ionization Cross ◽  
Total Ionization ◽  
Ion Production ◽  
Ionization Cross Sections

Ionization by protons in the energy range 100 to 450 keV has been investigated by means of the well-known parallel-plate condenser method. A uniform axial magnetic field enables slow ion collection to be carried out over a precisely determined path length at pressures low enough to ensure single collision conditions. The total cross-section for slow ion production cr+, and the total ionization cross-section have been determined for protons in hydrogen, helium , neon, argon and krypton. It is found that charge transfer is very small above about 200 keV so that cr+ ~ cr e . The ionization cross-section for all cases falls off as E -1 log E where E is the energy of relative motion. At the high-energy limit of the present measurements, the proton ionization cross-sections agree closely with electron ionization cross-sections for the same relative velocity of impact. The results are therefore in agreement with the general predictions of the Born approximation.

scholarly journals Electron-Collision-Induced Dissociative Ionization Cross Sections for Silane

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Satyendra Pal ◽  
Neeraj Kumar ◽  
Anshu
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Theoretical Data ◽  
Ionization Rate ◽  
Dissociative Ionization ◽  
Rate Coefficients ◽  
Electron Collision ◽  
Differential Cross Sections ◽  
Ionization Cross ◽  
Ionization Cross Sections

Secondary electron energy and angle dependent differential cross sections for the production of cations SiHn+ (n=0–3), H2+ and H+ resulting from dissociative ionization of SiH4by electron collision have been evaluated at fixed incident electron energies of 100 and 200 eV. The semiempirical formulation of Jain and Khare which requires the oscillator strength data as a major input has been employed. In the absence of experimental data for differential cross sections, the corresponding derived integral partial and total ionization cross sections in the energy range varying from ionization threshold to 1000 eV revealed a satisfactory agreement with the available experimental and theoretical data. We have also evaluated the ionization rate coefficients on the basis of calculated partial ionization cross sections and Maxwell-Boltzmann energy distributions.

ELECTRON IMPACT DISSOCIATIVE IONIZATION OF NITROSYL CHLORIDE

2012 ◽  
Vol 26 (11) ◽  
pp. 1250065 ◽  
Author(s):  
PENGQIAN WANG
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Three Dimensional ◽  
Ion Pair ◽  
Dissociative Ionization ◽  
Nitrosyl Chloride ◽  
Ionization Cross ◽  
Covariance Mapping

Electron impact dissociative ionization of nitrosyl chloride ( ClNO ) has been studied at the electron beam energy of 200 eV. The dissociation channels of up to triply ionized ClNO are investigated by two- and three-dimensional covariance mapping methods. The absolute cross-sections for the different dissociation channels are measured. No stable ClNO + or ClNO 2+ ions are observed in the mass spectrum. The most possible pathway for the dissociation of ClNO + is ClNO + → NO + + Cl . The total double ionization cross-section of ClNO is found to be 6.3% compared to the total single ionization cross-section. The main ion-pair dissociation channels for ClNO 2+ are ClNO 2+ → N + + O ++ Cl and ClNO 2+ → NO + + Cl +. The ClNO trications dissociate into either an ion pair or an ion triple, with comparable probabilities.

scholarly journals A Complete Cross Section Data Set for Electron Scattering by Pyridine: Modelling Electron Transport in the Energy Range 0–100 eV

2020 ◽  
Vol 21 (18) ◽  
pp. 6947
Author(s):  
Filipe Costa ◽  
Ali Traoré-Dubuis ◽  
Lidia Álvarez ◽  
Ana I. Lozano ◽  
Xueguang Ren ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Electron Scattering ◽  
Cross Sections ◽  
Transport Model ◽  
Theoretical Data ◽  
Double Differential Cross Section ◽  
Transmission Experiment ◽  
Data Set ◽  
Section Data

Electron scattering cross sections for pyridine in the energy range 0–100 eV, which we previously measured or calculated, have been critically compiled and complemented here with new measurements of electron energy loss spectra and double differential ionization cross sections. Experimental techniques employed in this study include a linear transmission apparatus and a reaction microscope system. To fulfill the transport model requirements, theoretical data have been recalculated within our independent atom model with screening corrected additivity rule and interference effects (IAM-SCAR) method for energies above 10 eV. In addition, results from the R-matrix and Schwinger multichannel with pseudopotential methods, for energies below 15 eV and 20 eV, respectively, are presented here. The reliability of this complete data set has been evaluated by comparing the simulated energy distribution of electrons transmitted through pyridine, with that observed in an electron-gas transmission experiment under magnetic confinement conditions. In addition, our representation of the angular distribution of the inelastically scattered electrons is discussed on the basis of the present double differential cross section experimental results.

Cross Section Ratios for the Electron Impact Production of Singly and Multiply Ionized Rare Gas Ions

1978 ◽  
Vol 33 (9) ◽  
pp. 1111-1113 ◽  
Author(s):  
F. Egger ◽  
T. D. Mark
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Impact Ionization ◽  
Rare Gas ◽  
Ionization Cross ◽  
Single Ionization ◽  
Multiple Ionization ◽  
Ionization Cross Sections

Electron impact ionization of He, Ne, Ar, Kr and Xe has been studied with a double focussing mass spectrometer Varian MAT CH5. Ratios of various multiple ionization cross sections with respect to single ionization cross sections for He, Ne, Ar, Kr and Xe at electron energies of 50, 100 and 150eV are given. These cross section ratios are com­pared with previous determinations.

Sign in / Sign up

Export Citation Format

Share Document