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 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 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.

Integral cross sections for electron-impact excitation of the 33S and 31S states of He near threshold

2006 ◽  
Vol 39 (6) ◽  
pp. 1547-1561 ◽  
Author(s):  
M Stepanović ◽  
M Minić ◽  
D Cvejanović ◽  
J Jureta ◽  
J Kurepa ◽  
...  
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Near Threshold
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