Electron impact excitation of the 2s22p3[4So]3s 5So2-2s22p4 3P2,1,0intercombination lines and of other observationally importantextreme-ultraviolet lines in Ne III

Abstract

Electron impact excitation collision strengths of doublyionized atomic neon (Ne III) are calculated in theclose-coupling approximation using the state-of-the-artR-matrix method. Twenty-eight 2s22p4, 2s2p5,2s22p33ℓ (ℓ = s,p,d),and 2s22p34s LS target terms, which comprise 56fine-structure levels, are retained in the present calculations.The effective collision strengths for astrophysically importantlines in the Ne III spectra are obtained by averaging theelectron collision strengths, for a wide range of incident electronenergies, over a Maxwellian distribution of velocities. Results arepresented for electron temperatures (Te in kelvins) in the range3.0⩽log Te⩽6.0,applicable to many laboratory and astrophysical plasmas. Thepresent results provide information on several importantastrophysically observed lines in the Ne III spectrumnecessary in order to quantitatively analyseexisting extreme-ultraviolet solar spectra.