Electron impact partial ionization cross sections of methyl alcohol up to 5 keV using the mass spectrometry data

2021 ◽  
Vol 75 (8) ◽  
Author(s):  
Kanupriya Goswami ◽  
Ajay Kumar Arora ◽  
Anand Bharadvaja ◽  
Kasturi Lal Baluja
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Methyl Alcohol ◽  
Cross Sections ◽  
Mass Spectrometry Data ◽  
Ionization Cross ◽  
Ionization Cross Sections

A Binary-Encounter-Bethe approach to compute electron-impact partial ionization cross sections of plasma relevant molecules like Hexamethyldisiloxane and Silane

2021 ◽  
Author(s):  
Ajay Kumar Arora ◽  
Krishna Kumar Gupta ◽  
Kanupriya Goswami ◽  
Anand Bharadvaja ◽  
K L Baluja
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Cross Sections ◽  
Mass Spectrometry Data ◽  
Ionization Cross ◽  
Total Ionization ◽  
Order Of Magnitude ◽  
Ionization Cross Sections ◽  
Theoretical Results ◽  
Binary Encounter

Abstract The electron-impact partial ionization cross sections (PICS) of the fragments are reported from threshold to 5~keV energy using the modified form of the binary-encounter-Bethe model. The scaling using mass spectrometry data ensures that the cross sections are of correct order of magnitude. The total ionization cross sections (TICS) were obtained by summing the PICS of fragments. The PICS and TICS obtained from the modified-binary-encounter-Bethe model are in excellent agreement with the experimental results and theoretical results. The molecules investigated are hexamethyldisiloxane (HMDSO) and silane. Both these species are highly relevant in plasma processing where the PICS are required over an extended energy range. The study of ionization process in conjunction with mass spectrometry provides correct estimates of the contribution that each charged ion makes to the TICS. The present approach can be easily extended to any species provided ion energetics, and relative cation abundances data are available.

Relative Variation of K- And L-Shell Ionization Cross Sections by Electron Impact

1999 ◽  
Vol 5 (S2) ◽  
pp. 584-585
Author(s):  
X. Llovet ◽  
C. Merlet ◽  
J.M. Fernández-Varea ◽  
F. Salvat
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Carbon Films ◽  
X Rays ◽  
Empirical Formulas ◽  
Relative Variation ◽  
Ionization Cross ◽  
Ionization Cross Sections ◽  
Semi Empirical ◽  
Shell Ionization

Knowledge of inner-shell ionization cross sections by electron impact is needed for quantitative procedures in electron probe microanalysis (EPMA) and Auger electron spectroscopy (AES) The common practice is to use semi-empirical formulas, based on the asymptotic limit of the Bethe theory, which sometimes are used beyond their domain of validity. Experimental measurements of ionization cross sections are scarce and affected by considerable uncertainties, thus a mere comparison with experimental data does not permit to draw a definite conclusion abou the accuracy of the various formulas. In this communication, we present new measurements o the relative variation of K- and L-shell ionization cross sections deduced from the counting rate of characteristic x-rays emitted by extremely thin films of Cr, Ni, Cu, Te, Au and Bi bombardec by keV electrons.The studied films were produced by thermal evaporation on backing self-supported 30 nm carbon films.

scholarly journals Electron-impact double ionization of the carbon atom

2018 ◽  
Vol 620 ◽  
pp. A188 ◽  
Author(s):  
Valdas Jonauskas
Keyword(s):  
Carbon Atom ◽  
Electron Impact ◽  
Cross Sections ◽  
Double Ionization ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Ionization Cross ◽  
Ionization Cross Sections ◽  
Good Agreement

Electron-impact single- and double-ionization cross sections and Maxwellian rate coefficients are presented for the carbon atom. Scaling factors are introduced for the electron-impact excitation and ionization cross sections obtained in the distorted wave (DW) approximation. It is shown that the scaled DW cross sections provide good agreement with measurements for the single ionization of the C atom and C1+ ion. The direct double-ionization (DDI) process is studied using a multi-step approach. Ionization–ionization, excitation–ionization–ionization, and ionization–excitation–ionization branches are analyzed. It is demonstrated that the three-step processes contribute ≼40% of the total DDI cross sections for the case where one of the electrons takes all of the excess energy after the first ionization process.

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