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Author(s):
V.P. Shevelko and H. Tawara
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Title:
Cross Sections for Electron-Impact Induced Transitions Between Excited States in He: n, n'=2,3 and 4
Date of publication:
Aug. 1995
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Key words:
excitation, electron scattenng, partial wave method, model potential, cross section, rate coefficient
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Abstract:
Cross sections sigma and corresponding maxwellian rate coefficients <v sigma> have been calculated for all 153 spin-allowed and spin-forbidden transitions between excited states in He with the principal quantum numbers n, n' = 2, 3 and 4 induced by electron impact. Calculations have been performed using Coulomb-Born approximation with exchange (CBE) in the partial wave representation with orthogonalized wave functions of the initial and final states in the incident electron energy range from threshold up to 2000 eV for spin-allowed transitions(Delta S=0) and up to 200 eV for spin-forbidden (intercombination, Delta S=1) transitions where the corresponding excitation cross sections are still relatively large. The fitting parameters for sigma and <v sigma> of spin-allowed transitions have been obtained. The results are compared with experimental data and other calculations.
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