Electron impact excitation of the 2s22p3[4So]3s 5So2-2s22p43P2,1,0 intercombination lines and of other observationally important extreme-ultraviolet lines in Ne III

Electron impact excitation collision strengths of doubly ionized atomic neon (Ne III) are calculated in the close-coupling approximation using the state-of-the-art R-matrix method. Twenty-eight 2s22p4, 2s2p5, 2s22p33 (l=s,p,d), and 2s22p34s LS target terms, which comprise 56 fine-structure levels, are retained in the present calculations. The effective collision strengths for astrophysically important lines in the Ne III spectra are obtained by averaging the electron collision strengths, for a wide range of incident electron energies, over a Maxwellian distribution of velocities. Results are presented for electron temperatures (Te in kelvins) in the range 3.0≤log Te≤6.0, applicable to many laboratory and astrophysical plasmas. The present results provide information on several important astrophysically observed lines in the Ne III spectrum necessary in order to quantitatively analyse existing extreme-ultraviolet solar spectra. (author)