
Author(s):
V.P. Shevelko and H. Tawara

Title:
Cross Sections for ElectronImpact Induced Transitions Between Excited States in He: n, n'=2,3 and 4
Date of publication:
Aug. 1995

Key words:
excitation, electron scattenng, partial wave method, model potential, cross section, rate coefficient

Abstract:
Cross sections sigma and corresponding maxwellian rate coefficients <v sigma> have been calculated for all 153 spinallowed and spinforbidden 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 CoulombBorn 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 spinallowed transitions(Delta S=0) and up to 200 eV for spinforbidden (intercombination, Delta S=1) transitions where the corresponding excitation cross sections are still relatively large. The fitting parameters for sigma and <v sigma> of spinallowed transitions have been obtained. The results are compared with experimental data and other calculations.

