scholarly journals Electron Impact Excitation of Extreme Ultra-Violet Transitions in Xe7+ – Xe10+ Ions

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Aloka Kumar Sahoo ◽  
Lalita Sharma
Keyword(s):  
Electron Impact ◽  
Electron Energy ◽  
Cross Sections ◽  
Energy Levels ◽  
Ultra Violet ◽  
High Energy ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Excitation Threshold

In the present work, a detailed study on the electron impact excitation of Xe7+, Xe8+, Xe9+ and Xe10+ ions for the dipole allowed (E1) transitions in the EUV range of 8–19 nm is presented. The multi-configuration Dirac–Fock method is used for the atomic structure calculation including the Breit and QED corrections along with the relativistic configuration interaction approach. We have compared our calculated energy levels, wavelengths and transition rates with other reported experimental and theoretical results. Further, the relativistic distorted wave method is used to calculate the cross sections from the excitation threshold to 3000 eV electron energy. For plasma physics applications, we have reported the fitting parameters of these cross sections using two different formulae for low and high energy ranges. The rate coefficients are also obtained using our calculated cross sections and considering the Maxwellian electron energy distribution function in the electron temperature range from 5 eV to 100 eV.

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.

scholarly journals Excitation of the lowest autoionizing level of caesium atoms by positron impact

2021 ◽  
Vol 2 (1) ◽  
pp. 77-83
Author(s):  
A. W. Munywoki ◽  
J. Okumu ◽  
C. S Singh
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
High Energy ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Distorted Wave ◽  
Positron Impact ◽  
Intermediate Energies ◽  
Threshold Energies ◽  
Determining Factor

We have obtained differential and integral cross sections for the excitation of caesium atom to the lowest autoionizing level by positron impact using the distorted wave approximation. We have also done calculations for electron impact excitation of the same level using the same method and compared our present positron/electron impact results with the available theoretical positron/ electron impact results and experimental electron impact results. It is found that the present positron impact integral cross sections are higher than the cross sections of Pangantiwar and Srivastava at low and intermediate energies, but the results converge as the energy increases in the high energy range. The disagreement at near threshold energies is due to the different distortion potentials used in the two calculations. The charge on the projectile is also a determining factor in the shape of the scattering cross section curves.

Electron-impact excitation of W40+–W43+ ions: Cross-section and polarization

2020 ◽  
Vol 34 (26) ◽  
pp. 2050241
Author(s):  
Neelam Shukla ◽  
Rajesh Srivastava
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Matrix Theory ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Excitation Threshold ◽  
Plasma Modeling ◽  
Excitation Cross Sections ◽  
Density Matrix Theory

Electron-impact excitation of tungsten ions [Formula: see text] has been studied using the fully relativistic distorted wave (RDW) theory. The excitation cross-sections of selected electric dipole allowed transitions of these ions to be determined for the incident electron energies from the excitation threshold to 20 keV. Further, the calculated cross-section results are fitted with an analytical expression for direct applications in plasma modeling. In addition, using the density matrix theory, the linear polarization of the photons emitted from the excited tungsten ions when decay to their respective ground states is presented.

Vacuum Ultraviolet Excitation of H(2p) by Electron Impact on H2

1972 ◽  
Vol 50 (18) ◽  
pp. 2211-2216 ◽  
Author(s):  
J. W. McConkey ◽  
F. G. Donaldson
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Vacuum Ultraviolet ◽  
High Energy ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Ultraviolet Excitation ◽  
A Value ◽  
High Energy Behavior ◽  
Energy Behavior

'Polarization-free' measurements are presented of the electron impact excitation of Lyman α by electron impact on H2 in the energy range 20–2000 eV. Cross sections are made absolute by normalizing to the data of Mumma and Zipf at 100 eV. A broad maximum in the function occurs around 60 eV, some 20 eV lower than was found by some previous workers. Reasons for this discrepancy are discussed. The high energy behavior of the cross section is analyzed in terms of the Bethe approximation and a value of 0.11 is obtained for the square of the dipole matrix element of the transitions involved.

scholarly journals Corrigendum

2020 ◽  
Vol 18 (1) ◽  
pp. 75-75
Author(s):  
E Editorial
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Ordinate Axis ◽  
The Cross ◽  
Font Color ◽  
Corrected Figure

The Editor-in-Chief has been informed that in the article ?Comparisons of Quantemol and Morgan LXCat cross section sets for electron-neutral scattering and rate-coefficients: helium and water?, FACTA UNIVERSITATIS, Series Physics, Chemistry and Technology Vol. 17, No 2, 2019, pp. 145-159, DOI: https://doi.org/10.2298/FUPCT1902145M, the cross sections for electron-impact excitation of helium in Figure 1b) are wrongly presented. The values of the cross section in the ordinate axis are marked in the interval from 10-1 to 101 (in units 10-16 cm2), and should be from 10-2 to 100. We apologize for that oversight. After further discussion with the corresponding author, the Editor-in-Chief has decided to publish a corrigendum with corrected Figure 1. Link to the corrected article: https://doi.org/10.2298/FUPCT1902145M <br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/FUPCT1902145M">10.2298/FUPCT1902145M</a></b></u>

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