EFFECTIVE COLLISION STRENGTHS FOR ELECTRON-IMPACT EXCITATION OF NE-IV

The multichannel R-matrix method is employed to compute effective coll ision strengths for electron-impact excitation of triply ionized neon. Eleven target eigenstates, represented by sophisticated configuration -interaction-type wave functions, are included in the close-coupling e xpansion, corresponding to 22j-resolved fine-structure levels connecte d by 231 transitions. The effective collision strengths, obtained by a veraging the collision strengths over a Maxwellian distribution of ele ctron velocities, are presented in tabular form for all 231 forbidden and allowed transitions over the wide range of electron temperatures f rom log T(K) = 4.7 to log T(K) = 5.8. This range encompasses the tempe ratures of particular importance for many astrophysical and plasma app lications. Enhancement of the effective collision strengths due to aut oionizing resonances converging to the target state thresholds is, as expected, a common feature for many of the forbidden transitions, wher eas contributions from the higher partial waves are found to be more i mportant for the allowed lines. The results presented in this paper ma ke up the most comprehensive tabulation to date of accurate effective collision strengths for the Ne IV ion. (C) 1998 Academic Press.