COLLISION STRENGTHS AND RATE COEFFICIENTS FOR ELECTRON-IMPACT EXCITATION IN HE-I - AN EXTRAPOLATION OF R-MATRIX CALCULATIONS TO HIGHER ELECTRON-IMPACT ENERGIES
Ac. Lanzafame et al., COLLISION STRENGTHS AND RATE COEFFICIENTS FOR ELECTRON-IMPACT EXCITATION IN HE-I - AN EXTRAPOLATION OF R-MATRIX CALCULATIONS TO HIGHER ELECTRON-IMPACT ENERGIES, Monthly Notices of the Royal Astronomical Society, 264(2), 1993, pp. 402-410
Extrapolations to higher electron impact energies of collision strengt
hs calculated using the R-matrix method are presented for electric dip
ole allowed transitions of neutral helium. The extrapolations are base
d on a spline fit constrained by the high-energy limiting behaviour de
duced from the Bethe approximation. This fit allows the calculation of
the rate coefficients over a wide temperature range. The possibility
of calculating collision rates in a non-equilibrium plasma is also dis
cussed.