Effective collision strengths for electron impact excitation of NI

We have calculated electron collisional excitation strengths for transition s among the 18 LS states 2s(2)2p(3) S-4(o), D-2(o), P-2(o); 2S(2)2p(2)(P-3) 3s(4)P, P-2; 2s2p(44)P; 2s(2)2p(2)(P-3)3p(2)S(o), D-4(o), P-4(o), S-4(o), D -2(o), P-2(o); 2s(2)2p(2)(D-1)3s D-2; 2s(2)2p(2)(P-3)4s P-4, P-2; and 2s(2) 2p(2)(P-3)3d P-2, P-4, D-2 of N I using the R-matrix method. These states a re represented by fairly extensive configuration-interaction wave functions . The 18 LS states give rise to 40 fine-structure levels. The calculated ex citation energies agree well with the measured values. The collision streng ths for fine-structure transitions are obtained using an algebraic transfor mation to intermediate coupling. The collision strengths are integrated ove r a Maxwellian distribution of electron energies to obtain effective collis ion strengths over a wide temperature range from 1000 to 600,000 K. The eff ective collision strengths obtained are tabulated for transitions among the lowest 12 LS states. (C) 2000 Academic Press.