Electron collisional excitation of Si (VIII): (1s(2)2s(2)2p(3) S-4(3/2)o, D-2(3/2,5/2)o, P-2(1/2,3/2)o) fine-structure transitions

Effective collision strengths for electron-impact excitation of the N-like ion Si VIII are calculated in the close-coupling approximation using the ab initio R-matrix method. The 22 fine-structure levels arising from the 11 l owest LS target states: 2s(2)2p3, 2S2p(4), 2p(5) and 2s(2)2p(2)3s are retai ned in the present calculation. The effective collision strengths for all f orbidden transitions within the 1s(2)2s(2)2p(3) S-4(3/2)o, D-2(3/2.5/2)o, P -2(1/2.3/2)o ground configuration levels are obtained by averaging the elec tron collision strengths, for a wide range of incident electron energies, o ver a Maxwellian distribution of velocities. Results are presented for elec tron temperatures in the range log T(K) = 3.3 to log T(K) = 6.5, applicable to many laboratory plasmas and in particular to astrophysical plasmas. We believe that the results are the most accurate to date and, indeed, the onl y data available which take account of resonance effects.