SEMIEMPIRICAL FORMULAS FOR CALCULATION OF L SUBSHELL IONIZATION CROSS SECTIONS

1994 ◽  
Vol 04 (04) ◽  
pp. 217-230 ◽  
Author(s):  
I. ORLIĆ ◽  
C.H. SOW ◽  
S.M. TANG

Presented are new parameters for the calculation of L subshell ionization cross sections for proton impact using a semiempirical expression. A similar paper was published by our group in early 1993 but the fitting parameters were obtained by using only 2295 experimental L shell cross section data. Since then a large number of experimental data have become available and therefore a new fitting has been performed employing more than 5000 data points. All available data were fitted separately for L1, L2 and L3 subshells. For targets with low atomic numbers (14≤Z≤42), only coefficients for L tot were obtained. Because of the slight Z dependence of the universal function, data were also devised into five sub-groups according to their atomic numbers and fitted separately within each group for L1, L2 and L3 subshells. To extend the energy range of validity of the new fitting function theoretical values were used in the high energy region where experimental data were lacking. Results are compared with ECPSSR predictions and discussed.




2012 ◽  
Vol 90 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Y. Wu ◽  
Z. An ◽  
Y.M. Duan ◽  
M.T. Liu ◽  
X.P. Ouyang

The absolute K-shell ionization cross sections of K and Lα X-ray production cross sections of I by 10–30 keV electron impact have been measured. The target was prepared by evaporating a thin film of compound KI to a thick pure carbon substrate. The effects of multiple scattering of electrons penetrating the target films, electrons reflected from the thick pure carbon substrates and bremsstrahlung photons produced when incident electrons impacted on the targets were corrected by using the Monte Carlo method. For K K-shell and I L-shell X-ray characteristic peaks, the spectra were fitted using the spectrum-fitting program ALLFIT to extract the Kα and Kβ peak counts more accurately for element K, and Lα peak counts for element I. The experimental results were compared with some theoretical results developed recently and available experimental data from the literature. The experimental data for I L-shell X-ray production cross sections by 10–30 keV electron impact are given here for the first time.



Author(s):  
Igor D. Kaganovich ◽  
Edward A. Startsev ◽  
Ronald C. Davidson ◽  
Steve R. Kecskemeti ◽  
Amitai Bin-Nun ◽  
...  


2012 ◽  
Vol 4 (2) ◽  
pp. 307
Author(s):  
F. Sabrin ◽  
M. A. Uddin ◽  
A. K. F. Haque

The Vaisburd and Evdokimov proposed an empirical model to calculate the electron impact single ionization cross-sections of atoms and molecules. The model has been applied to some atoms and molecules. To examine the efficiency of the model, the present work applies the model to calculate cross-sections for  Ne-isonuclear series Ne+, Ne2+, Ne3+, Ne4+, Ne5+, Ne6+, Ne7+, Ne8+, Ne9+ . The separate sets of values of the parameters of the model are determined by comparison with the available experimental data using a non-linear least-squares fitting computer code. Keywords: Electron impact ionization; Empirical model; Ionic targets. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i2.8704 J. Sci. Res. 4 (2), 307-313 (2012)



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.



2020 ◽  
Vol 98 (10) ◽  
pp. 970-975
Author(s):  
L.X. Tian ◽  
C.C. Dai ◽  
Y.J. Liu

The measurements of K-shell ionization cross sections for Fe, Ni, and Zn were performed using 7–29 keV electron impact on thick targets. Monte Carlo simulations were employed to correct the effects due to the multiple-scattered electrons and bremsstrahlung photons as well as other secondary particles within the thick targets. The so-called Tikhonov regularization method was adopted to deal with the ill-posed inverse problem involved in the thick-target method. The experimental results were compared with the DWBA and PWBA-C-Ex predictions as well as existing experimental data from the literature. It is observed that our experimental data are in better agreement with the theoretical results based on the DWBA model developed by Bote et al.



1975 ◽  
Vol 53 (11) ◽  
pp. 1044-1046 ◽  
Author(s):  
Suresh Chandra ◽  
Udit Narain

The ionization cross sections of N2 and O2 have been calculated in the energy range from threshold to 20 keV using a modified approach. The results are in good agreement with the available experimental data.



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