scholarly journals The effect of exchange and absorption potential in the distorted wave calculation of electron impact excitation of the autoionizing state of caesium

2020 ◽  
Vol 1 (1) ◽  
pp. 39-46
Author(s):  
A. A. Ochieng ◽  
J Okumu ◽  
C S Singh
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Cross Sections ◽  
Intermediate Energy ◽  
Impact Excitation ◽  
Experimental Result ◽  
Electron Impact Excitation ◽  
Distorted Wave ◽  
Autoionizing State ◽  
Absorption Potential

We have calculated the differential and integral cross sections for electron impact excitation of the lowest autoionizing level of caesium atoms in the energy range 13 – 500 eV using the distorted wave method. In this study we have used a complex distortion potential as the distortion potential both at the initial and the final channels. Our results are compared amongst themselves to establish the effect of exchange and imaginary absorption potentials. We also compared with other available theoretical and experimental results to determine the suitability of our present method. From the results it is seen that when an absorption potential is included in the distortion potential, the integral cross section moves closer to the experimental result in the intermediate energy range 19 – 40 eV.

Excitation of the Resonance Lines of Ar by Electrons

1973 ◽  
Vol 51 (9) ◽  
pp. 914-921 ◽  
Author(s):  
J. W. McConkey ◽  
F. G. Donaldson
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Oscillator Strength ◽  
Cross Sections ◽  
Experimental Results ◽  
Impact Excitation ◽  
Electron Impact Excitation

'Polarization-free' measurements are presented of the electron impact excitation of the 1048 Å and 1067 Å resonance lines of argon in the energy range 10–2000 eV. Cross sections are made absolute by normalizing to the optical oscillator strength of the 1048 Å line. Cascade is shown to play a major role in the excitation of the 4s levels. Comparison is made with other experimental results and with theory where available.

Relativistic Distorted-Wave Calculations of Electron Impact Excitation Cross Sections of Be-Like C 2+ Ions

2007 ◽  
Vol 24 (3) ◽  
pp. 691-694 ◽  
Author(s):  
Jiang Jun ◽  
Dong Chen-Zhong ◽  
Xie Lu-You ◽  
Wang Jian-Guo ◽  
Yan Jun ◽  
...  
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Distorted Wave ◽  
Excitation Cross Sections

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.

Excitation of the 3D states of helium by electrons and positrons

1996 ◽  
Vol 74 (7-8) ◽  
pp. 509-517 ◽  
Author(s):  
Surbhi Verma ◽  
Rajesh Srivastava
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Ground State ◽  
Stokes Parameters ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Distorted Wave ◽  
Positron Impact ◽  
Wave Approximation ◽  
Electrons And Positrons

Distorted-wave approximation calculations were carried out for the electron-impact excitation of 31,3D states from the 11S ground state of helium. Results are presented at an electron energy of 40 eV for the Stokes parameters P1-P4; coherence parameters Pl, γ, [Formula: see text], ρ00; and differential cross sections where most other theoretical and experimental data are available for comparison. The calculation is further extended to the positron-impact 11S–31D excitation in helium and comparison with the corresponding electron-impact results is discussed.

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